Chemistry previous year Neet questions MTG NEET Notes | EduRev

NEET : Chemistry previous year Neet questions MTG NEET Notes | EduRev

 Page 1


1.3 Properties of Matter and their Measurement
1. The dimensions of pressure are the same as that of
(a) force per unit volume
(b) energy per unit volume
(c) force (d) energy (1995)
1.4 Uncertainty in Measurement
2. Given the numbers : 161 cm, 0.161 cm, 0.0161 cm. The 
number of significant figures for the three numbers 
is
(a) 3, 3 and 4 respectively
(b) 3, 4 and 4 respectively
(c) 3, 4 and 5 respectively
(d) 3, 3 and 3 respectively. (1998)
1.5 Laws of Chemical Combinations
3. Equal masses of H
2
, O
2
 and methane  
have been taken in a container of volume V at 
temperature 27 °C in identical conditions. The ratio 
of the volumes of gases H
2
 : O
2
 : methane would be
(a) 8 : 16 : 1 (b) 16 : 8 : 1
(c) 16 : 1 : 2 (d) 8 : 1 : 2 (2014)
4. What volume of oxygen gas (O
2
) measured at 
0°C and 1 atm, is needed to burn completely 1 L 
of propane gas (C
3
H
8
) measured under the same 
conditions?
(a) 5 L (b) 10 L
(c) 7 L (d) 6 L (2008)
5. 0.24 g of a volatile gas, upon vaporisation, gives 45 mL 
vapour at NTP. What will be the vapour density of 
the substance? (Density of H
2
 = 0.089 g/L)
(a) 95.93 (b) 59.93 
(c) 95.39 (d) 5.993 (1996)
6. The molecular weight of O
2
 and SO
2
 are 32 and 
64 respectively. At 15°C and  150 mmHg pressure, 
one litre of O
2
 contains ‘N’ molecules. The number 
of molecules in two litres of SO
2
 under the same 
conditions of temperature and pressure will be
(a) N/2 (b) N
(c) 2 N (d) 4 N (1990)
7. What is the weight of oxygen required for the 
complete combustion of 2.8 kg of ethylene?
(a) 2.8 kg (b) 6.4 kg
(c) 9.6 kg (d) 96 kg (1989)
1.7 Atomic and Molecular Masses
8. An element, X has the following isotopic composition :
200
X : 90%       
199
X : 8.0%        
202
X : 2.0%
 The weighted average atomic mass of the naturally 
occurring element X is closest to 
(a) 201 amu (b) 202 amu
(c) 199 amu (d) 200 amu (2007)
9. Boron has two stable isotopes, 
10
B(19%) and 
11
B(81%). Calculate average at. wt. of boron in the 
periodic table.
(a) 10.8 (b) 10.2
(c) 11.2 (d) 10.0 (1990)
1.8 Mole Concept and Molar Masses
10. Which one of the followings has maximum number 
of atoms?
(a) 1 g of Ag
(s)
 [Atomic mass of Ag = 108]
(b) 1 g of Mg
(s)
 [Atomic mass of Mg = 24]
(c) 1 g of O
2(g)  
[Atomic mass of O = 16]
(d) 1 g of Li
(s)
 [Atomic mass of Li = 7]
(NEET 2020)
11. In which case is number of molecules of water 
maximum?
(a) 18 mL of water
(b) 0.18 g of water
(c) 0.00224 L of water vapours at 1 atm and 273 K
(d) 10
–3
 mol of water (NEET 2018)
12. Suppose the elements X and Y combine to form two 
compounds XY
2
 and X
3
Y
2
. When 0.1 mole of XY
2
 
weighs 10 g and 0.05 mole of X
3
Y
2
 weighs  9 g, the 
atomic weights of X and Y are
Some Basic Concepts 
of Chemistry
1
CHAPTER
Page 2


1.3 Properties of Matter and their Measurement
1. The dimensions of pressure are the same as that of
(a) force per unit volume
(b) energy per unit volume
(c) force (d) energy (1995)
1.4 Uncertainty in Measurement
2. Given the numbers : 161 cm, 0.161 cm, 0.0161 cm. The 
number of significant figures for the three numbers 
is
(a) 3, 3 and 4 respectively
(b) 3, 4 and 4 respectively
(c) 3, 4 and 5 respectively
(d) 3, 3 and 3 respectively. (1998)
1.5 Laws of Chemical Combinations
3. Equal masses of H
2
, O
2
 and methane  
have been taken in a container of volume V at 
temperature 27 °C in identical conditions. The ratio 
of the volumes of gases H
2
 : O
2
 : methane would be
(a) 8 : 16 : 1 (b) 16 : 8 : 1
(c) 16 : 1 : 2 (d) 8 : 1 : 2 (2014)
4. What volume of oxygen gas (O
2
) measured at 
0°C and 1 atm, is needed to burn completely 1 L 
of propane gas (C
3
H
8
) measured under the same 
conditions?
(a) 5 L (b) 10 L
(c) 7 L (d) 6 L (2008)
5. 0.24 g of a volatile gas, upon vaporisation, gives 45 mL 
vapour at NTP. What will be the vapour density of 
the substance? (Density of H
2
 = 0.089 g/L)
(a) 95.93 (b) 59.93 
(c) 95.39 (d) 5.993 (1996)
6. The molecular weight of O
2
 and SO
2
 are 32 and 
64 respectively. At 15°C and  150 mmHg pressure, 
one litre of O
2
 contains ‘N’ molecules. The number 
of molecules in two litres of SO
2
 under the same 
conditions of temperature and pressure will be
(a) N/2 (b) N
(c) 2 N (d) 4 N (1990)
7. What is the weight of oxygen required for the 
complete combustion of 2.8 kg of ethylene?
(a) 2.8 kg (b) 6.4 kg
(c) 9.6 kg (d) 96 kg (1989)
1.7 Atomic and Molecular Masses
8. An element, X has the following isotopic composition :
200
X : 90%       
199
X : 8.0%        
202
X : 2.0%
 The weighted average atomic mass of the naturally 
occurring element X is closest to 
(a) 201 amu (b) 202 amu
(c) 199 amu (d) 200 amu (2007)
9. Boron has two stable isotopes, 
10
B(19%) and 
11
B(81%). Calculate average at. wt. of boron in the 
periodic table.
(a) 10.8 (b) 10.2
(c) 11.2 (d) 10.0 (1990)
1.8 Mole Concept and Molar Masses
10. Which one of the followings has maximum number 
of atoms?
(a) 1 g of Ag
(s)
 [Atomic mass of Ag = 108]
(b) 1 g of Mg
(s)
 [Atomic mass of Mg = 24]
(c) 1 g of O
2(g)  
[Atomic mass of O = 16]
(d) 1 g of Li
(s)
 [Atomic mass of Li = 7]
(NEET 2020)
11. In which case is number of molecules of water 
maximum?
(a) 18 mL of water
(b) 0.18 g of water
(c) 0.00224 L of water vapours at 1 atm and 273 K
(d) 10
–3
 mol of water (NEET 2018)
12. Suppose the elements X and Y combine to form two 
compounds XY
2
 and X
3
Y
2
. When 0.1 mole of XY
2
 
weighs 10 g and 0.05 mole of X
3
Y
2
 weighs  9 g, the 
atomic weights of X and Y are
Some Basic Concepts 
of Chemistry
1
CHAPTER
2 NEET-AIPMT Chapterwise Topicwise Solutions Chemistry
(a) 40, 30 (b) 60, 40
(c) 20, 30 (d) 30, 20 (NEET-II 2016)
13. If Avogadro number N
A
, is changed from  
6.022 × 10
23
 mol
–1
 to 6.022 ×  10
20
 mol
–1
, this would 
change
(a) the mass of one mole of carbon
(b) the ratio of chemical species to each other in a 
balanced equation
(c) the ratio of elements to each other in a 
compound 
(d) the definition of mass in units of grams. (2015)
14. The number of water molecules is maximum in
(a) 1.8 gram of water
(b) 18 gram of water
(c) 18 moles of water
(d) 18 molecules of water. (2015)
15. A mixture of gases contains H
2
 and O
2
 gases in the 
ratio of 1 : 4 (w/w). What is the molar ratio of the 
two gases in the mixture?
(a) 16 : 1 (b) 2 : 1
(c) 1 : 4 (d) 4 : 1 (2015, Cancelled)
16. Which has the maximum number of molecules 
among the following?
(a) 44 g CO
2
 (b) 48 g O
3
(c) 8 g H
2
 (d) 64 g SO
2
  
(Mains 2011)
17. The number of atoms in 0.1 mol of a triatomic gas is 
(N
A
 = 6.02 × 10
23
 mol
–1
)
(a) 6.026 × 10
22
  (b) 1.806 × 10
23
(c) 3.600 × 10
23
  (d) 1.800 × 10
22
 (2010)
18. The maximum number of molecules is present in 
(a) 15 L of H
2
 gas at STP
(b) 5 L of N
2
 gas at STP
(c) 0.5 g of H
2
 gas 
(d) 10 g of O
2
 gas. (2004)
19. Which has maximum molecules?
(a) 7 g N
2
 (b) 2 g H
2
(c) 16 g NO
2
 (d) 16 g O
2
 (2002)
20. Specific volume of cylindrical virus particle is  
6.02 × 10
–2
 cc/g whose radius and length are 7 Å and 
10 Å respectively. If N
A
 = 6.02 × 10
23
, find molecular 
weight of virus.
(a) 15.4 kg/mol (b) 1.54 × 10
4
 kg/mol
(c) 3.08 × 10
4
 kg/mol (d) 3.08 × 10
3
 kg/mol
(2001)
21. The number of atoms in 4.25 g of NH
3
 is 
approximately
(a) 4 × 10
23
   (b) 2 × 10
23
(c) 1 × 10
23
   (d) 6 × 10
23
  (1999)
22. Haemoglobin contains 0.334% of iron by weight. The 
molecular weight of haemoglobin is approximately 
67200. The number of iron atoms (Atomic weight of 
Fe is 56) present in one molecule of haemoglobin is
(a) 4 (b) 6
(c) 3 (d) 2 (1998)
23. The number of moles of oxygen in one litre of air 
containing 21% oxygen by volume, under standard 
conditions, is
(a) 0.0093 mol (b) 2.10 mol
(c) 0.186 mol (d) 0.21 mol             (1995)
24. The total number of valence electrons in 4.2 g of N
3
–
 
ion is (N
A
 is the Avogadro’s number)
(a) 2.1 N
A
 (b) 4.2 N
A
(c) 1.6 N
A
 (d) 3.2 N
A
 (1994)
25. The number of gram molecules of oxygen in  
6.02 × 10
24
 CO molecules is
(a) 10 g molecules (b) 5 g molecules
(c) 1 g molecule (d) 0.5 g molecules. 
(1990)
26. Ratio of C
p
 and C
v
 of a gas ‘X’ is 1.4. The number  
of atoms of the gas ‘X’ present in 11.2 litres of it at 
NTP will be
(a) 6.02 × 10
23
  (b) 1.2 × 10
23
(c) 3.01 × 10
23
  (d) 2.01 × 10
23
 (1989)
27. The number of oxygen atoms in 4.4 g of CO
2
 is
(a) 1.2 × 10
23
 (b) 6 × 10
22
(c) 6 × 10
23
 (d) 12 × 10
23 
(1989)
28. 1 cc N
2
O at NTP contains
(a) 
18
224
10
22
.
× atoms
(b) 
602
22400
10
23
.
× molecules
(c) 
132
224
10
23
.
× electrons
 
(d) all of the above. (1988)
1.9 Percentage Composition
29. An organic compound contains carbon, hydrogen 
and oxygen. Its elemental analysis gave C, 38.71% 
and H, 9.67%. The empirical formula of the 
compound would be
(a) CHO (b) CH
4
O
(c) CH
3
O (d) CH
2
O (2008)
30. Percentage of Se in peroxidase anhydrous enzyme 
is 0.5% by weight (at. wt. = 78.4) then minimum 
molecular weight of peroxidase anhydrous enzyme is
(a) 1.568 × 10
4
 (b) 1.568 × 10
3
(c) 15.68 (d) 2.136 × 10
4
        (2001)
Page 3


1.3 Properties of Matter and their Measurement
1. The dimensions of pressure are the same as that of
(a) force per unit volume
(b) energy per unit volume
(c) force (d) energy (1995)
1.4 Uncertainty in Measurement
2. Given the numbers : 161 cm, 0.161 cm, 0.0161 cm. The 
number of significant figures for the three numbers 
is
(a) 3, 3 and 4 respectively
(b) 3, 4 and 4 respectively
(c) 3, 4 and 5 respectively
(d) 3, 3 and 3 respectively. (1998)
1.5 Laws of Chemical Combinations
3. Equal masses of H
2
, O
2
 and methane  
have been taken in a container of volume V at 
temperature 27 °C in identical conditions. The ratio 
of the volumes of gases H
2
 : O
2
 : methane would be
(a) 8 : 16 : 1 (b) 16 : 8 : 1
(c) 16 : 1 : 2 (d) 8 : 1 : 2 (2014)
4. What volume of oxygen gas (O
2
) measured at 
0°C and 1 atm, is needed to burn completely 1 L 
of propane gas (C
3
H
8
) measured under the same 
conditions?
(a) 5 L (b) 10 L
(c) 7 L (d) 6 L (2008)
5. 0.24 g of a volatile gas, upon vaporisation, gives 45 mL 
vapour at NTP. What will be the vapour density of 
the substance? (Density of H
2
 = 0.089 g/L)
(a) 95.93 (b) 59.93 
(c) 95.39 (d) 5.993 (1996)
6. The molecular weight of O
2
 and SO
2
 are 32 and 
64 respectively. At 15°C and  150 mmHg pressure, 
one litre of O
2
 contains ‘N’ molecules. The number 
of molecules in two litres of SO
2
 under the same 
conditions of temperature and pressure will be
(a) N/2 (b) N
(c) 2 N (d) 4 N (1990)
7. What is the weight of oxygen required for the 
complete combustion of 2.8 kg of ethylene?
(a) 2.8 kg (b) 6.4 kg
(c) 9.6 kg (d) 96 kg (1989)
1.7 Atomic and Molecular Masses
8. An element, X has the following isotopic composition :
200
X : 90%       
199
X : 8.0%        
202
X : 2.0%
 The weighted average atomic mass of the naturally 
occurring element X is closest to 
(a) 201 amu (b) 202 amu
(c) 199 amu (d) 200 amu (2007)
9. Boron has two stable isotopes, 
10
B(19%) and 
11
B(81%). Calculate average at. wt. of boron in the 
periodic table.
(a) 10.8 (b) 10.2
(c) 11.2 (d) 10.0 (1990)
1.8 Mole Concept and Molar Masses
10. Which one of the followings has maximum number 
of atoms?
(a) 1 g of Ag
(s)
 [Atomic mass of Ag = 108]
(b) 1 g of Mg
(s)
 [Atomic mass of Mg = 24]
(c) 1 g of O
2(g)  
[Atomic mass of O = 16]
(d) 1 g of Li
(s)
 [Atomic mass of Li = 7]
(NEET 2020)
11. In which case is number of molecules of water 
maximum?
(a) 18 mL of water
(b) 0.18 g of water
(c) 0.00224 L of water vapours at 1 atm and 273 K
(d) 10
–3
 mol of water (NEET 2018)
12. Suppose the elements X and Y combine to form two 
compounds XY
2
 and X
3
Y
2
. When 0.1 mole of XY
2
 
weighs 10 g and 0.05 mole of X
3
Y
2
 weighs  9 g, the 
atomic weights of X and Y are
Some Basic Concepts 
of Chemistry
1
CHAPTER
2 NEET-AIPMT Chapterwise Topicwise Solutions Chemistry
(a) 40, 30 (b) 60, 40
(c) 20, 30 (d) 30, 20 (NEET-II 2016)
13. If Avogadro number N
A
, is changed from  
6.022 × 10
23
 mol
–1
 to 6.022 ×  10
20
 mol
–1
, this would 
change
(a) the mass of one mole of carbon
(b) the ratio of chemical species to each other in a 
balanced equation
(c) the ratio of elements to each other in a 
compound 
(d) the definition of mass in units of grams. (2015)
14. The number of water molecules is maximum in
(a) 1.8 gram of water
(b) 18 gram of water
(c) 18 moles of water
(d) 18 molecules of water. (2015)
15. A mixture of gases contains H
2
 and O
2
 gases in the 
ratio of 1 : 4 (w/w). What is the molar ratio of the 
two gases in the mixture?
(a) 16 : 1 (b) 2 : 1
(c) 1 : 4 (d) 4 : 1 (2015, Cancelled)
16. Which has the maximum number of molecules 
among the following?
(a) 44 g CO
2
 (b) 48 g O
3
(c) 8 g H
2
 (d) 64 g SO
2
  
(Mains 2011)
17. The number of atoms in 0.1 mol of a triatomic gas is 
(N
A
 = 6.02 × 10
23
 mol
–1
)
(a) 6.026 × 10
22
  (b) 1.806 × 10
23
(c) 3.600 × 10
23
  (d) 1.800 × 10
22
 (2010)
18. The maximum number of molecules is present in 
(a) 15 L of H
2
 gas at STP
(b) 5 L of N
2
 gas at STP
(c) 0.5 g of H
2
 gas 
(d) 10 g of O
2
 gas. (2004)
19. Which has maximum molecules?
(a) 7 g N
2
 (b) 2 g H
2
(c) 16 g NO
2
 (d) 16 g O
2
 (2002)
20. Specific volume of cylindrical virus particle is  
6.02 × 10
–2
 cc/g whose radius and length are 7 Å and 
10 Å respectively. If N
A
 = 6.02 × 10
23
, find molecular 
weight of virus.
(a) 15.4 kg/mol (b) 1.54 × 10
4
 kg/mol
(c) 3.08 × 10
4
 kg/mol (d) 3.08 × 10
3
 kg/mol
(2001)
21. The number of atoms in 4.25 g of NH
3
 is 
approximately
(a) 4 × 10
23
   (b) 2 × 10
23
(c) 1 × 10
23
   (d) 6 × 10
23
  (1999)
22. Haemoglobin contains 0.334% of iron by weight. The 
molecular weight of haemoglobin is approximately 
67200. The number of iron atoms (Atomic weight of 
Fe is 56) present in one molecule of haemoglobin is
(a) 4 (b) 6
(c) 3 (d) 2 (1998)
23. The number of moles of oxygen in one litre of air 
containing 21% oxygen by volume, under standard 
conditions, is
(a) 0.0093 mol (b) 2.10 mol
(c) 0.186 mol (d) 0.21 mol             (1995)
24. The total number of valence electrons in 4.2 g of N
3
–
 
ion is (N
A
 is the Avogadro’s number)
(a) 2.1 N
A
 (b) 4.2 N
A
(c) 1.6 N
A
 (d) 3.2 N
A
 (1994)
25. The number of gram molecules of oxygen in  
6.02 × 10
24
 CO molecules is
(a) 10 g molecules (b) 5 g molecules
(c) 1 g molecule (d) 0.5 g molecules. 
(1990)
26. Ratio of C
p
 and C
v
 of a gas ‘X’ is 1.4. The number  
of atoms of the gas ‘X’ present in 11.2 litres of it at 
NTP will be
(a) 6.02 × 10
23
  (b) 1.2 × 10
23
(c) 3.01 × 10
23
  (d) 2.01 × 10
23
 (1989)
27. The number of oxygen atoms in 4.4 g of CO
2
 is
(a) 1.2 × 10
23
 (b) 6 × 10
22
(c) 6 × 10
23
 (d) 12 × 10
23 
(1989)
28. 1 cc N
2
O at NTP contains
(a) 
18
224
10
22
.
× atoms
(b) 
602
22400
10
23
.
× molecules
(c) 
132
224
10
23
.
× electrons
 
(d) all of the above. (1988)
1.9 Percentage Composition
29. An organic compound contains carbon, hydrogen 
and oxygen. Its elemental analysis gave C, 38.71% 
and H, 9.67%. The empirical formula of the 
compound would be
(a) CHO (b) CH
4
O
(c) CH
3
O (d) CH
2
O (2008)
30. Percentage of Se in peroxidase anhydrous enzyme 
is 0.5% by weight (at. wt. = 78.4) then minimum 
molecular weight of peroxidase anhydrous enzyme is
(a) 1.568 × 10
4
 (b) 1.568 × 10
3
(c) 15.68 (d) 2.136 × 10
4
        (2001)
3 Some Basic Concepts of Chemistry
31. Which of the following fertilizers has the highest 
nitrogen percentage?
(a) Ammonium sulphate
(b) Calcium cyanamide
(c) Urea
(d) Ammonium nitrate (1993)
1.10 Stoichiometry and Stoichiometric   
  Calculations
32. The number of moles of hydrogen molecules 
required to produce 20 moles of ammonia through 
Haber’s process is 
(a) 40 (b) 10
(c) 20 (d) 30 (NEET 2019)
33. The density of 2 M aqueous solution of NaOH is 
1.28 g/cm
3
. The molality of the solution is [Given 
that molecular mass of NaOH = 40 g mol
–1
]
(a) 1.20 m   (b) 1.56 m
(c) 1.67 m   (d) 1.32 m
(Odisha NEET 2019)
34. A mixture of 2.3 g formic acid and 4.5 g oxalic acid 
is treated with conc. H
2
SO
4
. The evolved gaseous 
mixture is passed through KOH pellets. Weight (in g) 
of the remaining product at STP will be
(a) 1.4 (b) 3.0
(c) 2.8 (d) 4.4 (NEET 2018)
35. What is the mass of the precipitate formed when  
50 mL of 16.9% solution of AgNO
3
 is mixed with  
50 mL of 5.8% NaCl solution?
(Ag = 107.8, N = 14, O = 16, Na = 23, Cl = 35.5) 
(a) 3.5 g (b) 7 g
(c) 14 g (d) 28 g (2015)
36. 20.0 g of a magnesium carbonate sample 
decomposes on heating to give carbon dioxide and 
8.0 g magnesium oxide. What will be the percentage 
purity of magnesium carbonate in the sample?
(At. wt. of Mg = 24)
(a) 96   (b) 60 
(c) 84   (d) 75 (2015)
37. When 22.4 litres of H
2(g)
 is mixed with 11.2 litres 
of Cl
2(g)
, each at STP, the moles of HCl
(g)
 formed is 
equal to
(a) 1 mol of HCl
(g)
 (b) 2 mol of HCl
(g)
(c) 0.5 mol of HCl
(g)
 (d) 1.5 mol of HCl
(g)
(2014)
38. 1.0 g of magnesium is burnt with 0.56 g O
2
 in a 
closed vessel. Which reactant is left in excess and 
how much? (At. wt. Mg = 24, O = 16)
(a) Mg, 0.16 g (b) O
2
, 0.16 g
(c) Mg, 0.44 g (d) O
2
, 0.28 g (2014)
39. 6.02 × 10
20
 molecules of urea are present in 100 mL 
of its solution. The concentration of solution is 
(a) 0.001 M (b) 0.1 M
(c) 0.02 M (d) 0.01 M
(NEET 2013)
40. In an experiment it showed that 10 mL of 0.05 M 
solution of chloride required 10 mL of 0.1 M 
solution of AgNO
3
, which of the following will be 
the formula of the chloride (X stands for the symbol 
of the element other than chlorine)?
(a) X
2
Cl
2
 (b) XCl
2
(c) XCl
4
 (d) X
2
Cl
(Karnataka NEET 2013)
41. 25.3 g of sodium carbonate, Na
2
CO
3
 is dissolved in 
enough water to make 250 mL of solution. If sodium 
carbonate dissociates completely, molar concentration 
of sodium ion, Na
+
 and carbonate ions, CO
3
2–
 are 
respectively
 (Molar mass of Na
2
CO
3
 = 106 g mol
–1
)
(a) 0.955 M and 1.910 M
(b) 1.910 M and 0.955 M
(c) 1.90 M and 1.910 M
(d) 0.477 M and 0.477 M (2010)
42. 10 g of hydrogen and 64 g of oxygen were filled in a 
steel vessel and exploded. Amount of water produced 
in this reaction will be
(a) 3 mol (b) 4 mol
(c) 1 mol (d) 2 mol (2009)
43. How many moles of lead(II) chloride will be formed 
from a reaction between 6.5 g of PbO and 3.2 g HCl?
(a) 0.011 (b) 0.029
(c) 0.044 (d) 0.333 (2008)
44. The mass of carbon anode consumed (giving only 
carbon dioxide) in the production of 270 kg of 
aluminium metal from bauxite by the Hall process is 
(a) 270 kg (b) 540 kg
(c) 90 kg (d) 180 kg
(Atomic mass : Al = 27)   (2005)
45. Molarity of liquid HCl, if density of solution is  
1.17 g/cc is 
(a) 36.5 (b) 18.25
(c) 32.05 (d) 42.10 (2001)
46. Volume of CO
2
 obtained by the complete 
decomposition of 9.85 g of BaCO
3
 is
(a) 2.24 L (b) 1.12 L
(c) 0.84 L (d) 0.56 L (2000)
Page 4


1.3 Properties of Matter and their Measurement
1. The dimensions of pressure are the same as that of
(a) force per unit volume
(b) energy per unit volume
(c) force (d) energy (1995)
1.4 Uncertainty in Measurement
2. Given the numbers : 161 cm, 0.161 cm, 0.0161 cm. The 
number of significant figures for the three numbers 
is
(a) 3, 3 and 4 respectively
(b) 3, 4 and 4 respectively
(c) 3, 4 and 5 respectively
(d) 3, 3 and 3 respectively. (1998)
1.5 Laws of Chemical Combinations
3. Equal masses of H
2
, O
2
 and methane  
have been taken in a container of volume V at 
temperature 27 °C in identical conditions. The ratio 
of the volumes of gases H
2
 : O
2
 : methane would be
(a) 8 : 16 : 1 (b) 16 : 8 : 1
(c) 16 : 1 : 2 (d) 8 : 1 : 2 (2014)
4. What volume of oxygen gas (O
2
) measured at 
0°C and 1 atm, is needed to burn completely 1 L 
of propane gas (C
3
H
8
) measured under the same 
conditions?
(a) 5 L (b) 10 L
(c) 7 L (d) 6 L (2008)
5. 0.24 g of a volatile gas, upon vaporisation, gives 45 mL 
vapour at NTP. What will be the vapour density of 
the substance? (Density of H
2
 = 0.089 g/L)
(a) 95.93 (b) 59.93 
(c) 95.39 (d) 5.993 (1996)
6. The molecular weight of O
2
 and SO
2
 are 32 and 
64 respectively. At 15°C and  150 mmHg pressure, 
one litre of O
2
 contains ‘N’ molecules. The number 
of molecules in two litres of SO
2
 under the same 
conditions of temperature and pressure will be
(a) N/2 (b) N
(c) 2 N (d) 4 N (1990)
7. What is the weight of oxygen required for the 
complete combustion of 2.8 kg of ethylene?
(a) 2.8 kg (b) 6.4 kg
(c) 9.6 kg (d) 96 kg (1989)
1.7 Atomic and Molecular Masses
8. An element, X has the following isotopic composition :
200
X : 90%       
199
X : 8.0%        
202
X : 2.0%
 The weighted average atomic mass of the naturally 
occurring element X is closest to 
(a) 201 amu (b) 202 amu
(c) 199 amu (d) 200 amu (2007)
9. Boron has two stable isotopes, 
10
B(19%) and 
11
B(81%). Calculate average at. wt. of boron in the 
periodic table.
(a) 10.8 (b) 10.2
(c) 11.2 (d) 10.0 (1990)
1.8 Mole Concept and Molar Masses
10. Which one of the followings has maximum number 
of atoms?
(a) 1 g of Ag
(s)
 [Atomic mass of Ag = 108]
(b) 1 g of Mg
(s)
 [Atomic mass of Mg = 24]
(c) 1 g of O
2(g)  
[Atomic mass of O = 16]
(d) 1 g of Li
(s)
 [Atomic mass of Li = 7]
(NEET 2020)
11. In which case is number of molecules of water 
maximum?
(a) 18 mL of water
(b) 0.18 g of water
(c) 0.00224 L of water vapours at 1 atm and 273 K
(d) 10
–3
 mol of water (NEET 2018)
12. Suppose the elements X and Y combine to form two 
compounds XY
2
 and X
3
Y
2
. When 0.1 mole of XY
2
 
weighs 10 g and 0.05 mole of X
3
Y
2
 weighs  9 g, the 
atomic weights of X and Y are
Some Basic Concepts 
of Chemistry
1
CHAPTER
2 NEET-AIPMT Chapterwise Topicwise Solutions Chemistry
(a) 40, 30 (b) 60, 40
(c) 20, 30 (d) 30, 20 (NEET-II 2016)
13. If Avogadro number N
A
, is changed from  
6.022 × 10
23
 mol
–1
 to 6.022 ×  10
20
 mol
–1
, this would 
change
(a) the mass of one mole of carbon
(b) the ratio of chemical species to each other in a 
balanced equation
(c) the ratio of elements to each other in a 
compound 
(d) the definition of mass in units of grams. (2015)
14. The number of water molecules is maximum in
(a) 1.8 gram of water
(b) 18 gram of water
(c) 18 moles of water
(d) 18 molecules of water. (2015)
15. A mixture of gases contains H
2
 and O
2
 gases in the 
ratio of 1 : 4 (w/w). What is the molar ratio of the 
two gases in the mixture?
(a) 16 : 1 (b) 2 : 1
(c) 1 : 4 (d) 4 : 1 (2015, Cancelled)
16. Which has the maximum number of molecules 
among the following?
(a) 44 g CO
2
 (b) 48 g O
3
(c) 8 g H
2
 (d) 64 g SO
2
  
(Mains 2011)
17. The number of atoms in 0.1 mol of a triatomic gas is 
(N
A
 = 6.02 × 10
23
 mol
–1
)
(a) 6.026 × 10
22
  (b) 1.806 × 10
23
(c) 3.600 × 10
23
  (d) 1.800 × 10
22
 (2010)
18. The maximum number of molecules is present in 
(a) 15 L of H
2
 gas at STP
(b) 5 L of N
2
 gas at STP
(c) 0.5 g of H
2
 gas 
(d) 10 g of O
2
 gas. (2004)
19. Which has maximum molecules?
(a) 7 g N
2
 (b) 2 g H
2
(c) 16 g NO
2
 (d) 16 g O
2
 (2002)
20. Specific volume of cylindrical virus particle is  
6.02 × 10
–2
 cc/g whose radius and length are 7 Å and 
10 Å respectively. If N
A
 = 6.02 × 10
23
, find molecular 
weight of virus.
(a) 15.4 kg/mol (b) 1.54 × 10
4
 kg/mol
(c) 3.08 × 10
4
 kg/mol (d) 3.08 × 10
3
 kg/mol
(2001)
21. The number of atoms in 4.25 g of NH
3
 is 
approximately
(a) 4 × 10
23
   (b) 2 × 10
23
(c) 1 × 10
23
   (d) 6 × 10
23
  (1999)
22. Haemoglobin contains 0.334% of iron by weight. The 
molecular weight of haemoglobin is approximately 
67200. The number of iron atoms (Atomic weight of 
Fe is 56) present in one molecule of haemoglobin is
(a) 4 (b) 6
(c) 3 (d) 2 (1998)
23. The number of moles of oxygen in one litre of air 
containing 21% oxygen by volume, under standard 
conditions, is
(a) 0.0093 mol (b) 2.10 mol
(c) 0.186 mol (d) 0.21 mol             (1995)
24. The total number of valence electrons in 4.2 g of N
3
–
 
ion is (N
A
 is the Avogadro’s number)
(a) 2.1 N
A
 (b) 4.2 N
A
(c) 1.6 N
A
 (d) 3.2 N
A
 (1994)
25. The number of gram molecules of oxygen in  
6.02 × 10
24
 CO molecules is
(a) 10 g molecules (b) 5 g molecules
(c) 1 g molecule (d) 0.5 g molecules. 
(1990)
26. Ratio of C
p
 and C
v
 of a gas ‘X’ is 1.4. The number  
of atoms of the gas ‘X’ present in 11.2 litres of it at 
NTP will be
(a) 6.02 × 10
23
  (b) 1.2 × 10
23
(c) 3.01 × 10
23
  (d) 2.01 × 10
23
 (1989)
27. The number of oxygen atoms in 4.4 g of CO
2
 is
(a) 1.2 × 10
23
 (b) 6 × 10
22
(c) 6 × 10
23
 (d) 12 × 10
23 
(1989)
28. 1 cc N
2
O at NTP contains
(a) 
18
224
10
22
.
× atoms
(b) 
602
22400
10
23
.
× molecules
(c) 
132
224
10
23
.
× electrons
 
(d) all of the above. (1988)
1.9 Percentage Composition
29. An organic compound contains carbon, hydrogen 
and oxygen. Its elemental analysis gave C, 38.71% 
and H, 9.67%. The empirical formula of the 
compound would be
(a) CHO (b) CH
4
O
(c) CH
3
O (d) CH
2
O (2008)
30. Percentage of Se in peroxidase anhydrous enzyme 
is 0.5% by weight (at. wt. = 78.4) then minimum 
molecular weight of peroxidase anhydrous enzyme is
(a) 1.568 × 10
4
 (b) 1.568 × 10
3
(c) 15.68 (d) 2.136 × 10
4
        (2001)
3 Some Basic Concepts of Chemistry
31. Which of the following fertilizers has the highest 
nitrogen percentage?
(a) Ammonium sulphate
(b) Calcium cyanamide
(c) Urea
(d) Ammonium nitrate (1993)
1.10 Stoichiometry and Stoichiometric   
  Calculations
32. The number of moles of hydrogen molecules 
required to produce 20 moles of ammonia through 
Haber’s process is 
(a) 40 (b) 10
(c) 20 (d) 30 (NEET 2019)
33. The density of 2 M aqueous solution of NaOH is 
1.28 g/cm
3
. The molality of the solution is [Given 
that molecular mass of NaOH = 40 g mol
–1
]
(a) 1.20 m   (b) 1.56 m
(c) 1.67 m   (d) 1.32 m
(Odisha NEET 2019)
34. A mixture of 2.3 g formic acid and 4.5 g oxalic acid 
is treated with conc. H
2
SO
4
. The evolved gaseous 
mixture is passed through KOH pellets. Weight (in g) 
of the remaining product at STP will be
(a) 1.4 (b) 3.0
(c) 2.8 (d) 4.4 (NEET 2018)
35. What is the mass of the precipitate formed when  
50 mL of 16.9% solution of AgNO
3
 is mixed with  
50 mL of 5.8% NaCl solution?
(Ag = 107.8, N = 14, O = 16, Na = 23, Cl = 35.5) 
(a) 3.5 g (b) 7 g
(c) 14 g (d) 28 g (2015)
36. 20.0 g of a magnesium carbonate sample 
decomposes on heating to give carbon dioxide and 
8.0 g magnesium oxide. What will be the percentage 
purity of magnesium carbonate in the sample?
(At. wt. of Mg = 24)
(a) 96   (b) 60 
(c) 84   (d) 75 (2015)
37. When 22.4 litres of H
2(g)
 is mixed with 11.2 litres 
of Cl
2(g)
, each at STP, the moles of HCl
(g)
 formed is 
equal to
(a) 1 mol of HCl
(g)
 (b) 2 mol of HCl
(g)
(c) 0.5 mol of HCl
(g)
 (d) 1.5 mol of HCl
(g)
(2014)
38. 1.0 g of magnesium is burnt with 0.56 g O
2
 in a 
closed vessel. Which reactant is left in excess and 
how much? (At. wt. Mg = 24, O = 16)
(a) Mg, 0.16 g (b) O
2
, 0.16 g
(c) Mg, 0.44 g (d) O
2
, 0.28 g (2014)
39. 6.02 × 10
20
 molecules of urea are present in 100 mL 
of its solution. The concentration of solution is 
(a) 0.001 M (b) 0.1 M
(c) 0.02 M (d) 0.01 M
(NEET 2013)
40. In an experiment it showed that 10 mL of 0.05 M 
solution of chloride required 10 mL of 0.1 M 
solution of AgNO
3
, which of the following will be 
the formula of the chloride (X stands for the symbol 
of the element other than chlorine)?
(a) X
2
Cl
2
 (b) XCl
2
(c) XCl
4
 (d) X
2
Cl
(Karnataka NEET 2013)
41. 25.3 g of sodium carbonate, Na
2
CO
3
 is dissolved in 
enough water to make 250 mL of solution. If sodium 
carbonate dissociates completely, molar concentration 
of sodium ion, Na
+
 and carbonate ions, CO
3
2–
 are 
respectively
 (Molar mass of Na
2
CO
3
 = 106 g mol
–1
)
(a) 0.955 M and 1.910 M
(b) 1.910 M and 0.955 M
(c) 1.90 M and 1.910 M
(d) 0.477 M and 0.477 M (2010)
42. 10 g of hydrogen and 64 g of oxygen were filled in a 
steel vessel and exploded. Amount of water produced 
in this reaction will be
(a) 3 mol (b) 4 mol
(c) 1 mol (d) 2 mol (2009)
43. How many moles of lead(II) chloride will be formed 
from a reaction between 6.5 g of PbO and 3.2 g HCl?
(a) 0.011 (b) 0.029
(c) 0.044 (d) 0.333 (2008)
44. The mass of carbon anode consumed (giving only 
carbon dioxide) in the production of 270 kg of 
aluminium metal from bauxite by the Hall process is 
(a) 270 kg (b) 540 kg
(c) 90 kg (d) 180 kg
(Atomic mass : Al = 27)   (2005)
45. Molarity of liquid HCl, if density of solution is  
1.17 g/cc is 
(a) 36.5 (b) 18.25
(c) 32.05 (d) 42.10 (2001)
46. Volume of CO
2
 obtained by the complete 
decomposition of 9.85 g of BaCO
3
 is
(a) 2.24 L (b) 1.12 L
(c) 0.84 L (d) 0.56 L (2000)
4 NEET-AIPMT Chapterwise Topicwise Solutions Chemistry
47. In the reaction,
 4NH
3(g)
 + 5O
2(g)
 ? 4NO
(g)
 + 6H
2
O
(l)
 when 1 mole of ammonia and 1 mole of O
2
 are made 
to react to completion
(a) all the oxygen will be consumed
(b) 1.0 mole of NO will be produced
(c) 1.0 mole of H
2
O is produced
(d) all the ammonia will be consumed. (1998)
48. The amount of zinc required to produce 224 mL of 
H
2
 at STP on treatment with dilute H
2
SO
4
 will be
(a) 65 g (b) 0.065 g
(c) 0.65 g (d) 6.5 g (1996)
49. At STP the density of CCl
4
 vapour in g/L will be 
nearest to
(a) 6.87   (b) 3.42
(c) 10.26   (d) 4.57 (1988)
ANSWER KEY
1. (b) 2. (d) 3. (c) 4. (a) 5. (b) 6. (c) 7. (c) 8. (d) 9. (a) 10. (d) 
11. (a) 12. (a) 13. (a) 14. (c) 15. (d) 16. (c) 17. (b) 18. (a) 19. (b) 20. (a) 
21. (d)  22. (a) 23. (a)  24. (c) 25. (b) 26. (a) 27. (a) 28. (d) 29. (c) 30. (a) 
31. (c) 32. (d) 33. (c)  34. (c) 35. (b) 36. (c) 37. (a) 38. (a) 39. (d)  40. (b) 
41. (b) 42. (b) 43. (b) 44. (c) 45. (c) 46. (b) 47. (a) 48. (c) 49. (a)
1. (b) : Pressure=
Force
Area
Therefore, dimensions of pressure =
-
MLT
L
2
2
 = ML
–1
T
–2
 
and dimensions of energy per unit volume 
 
= = =
-
--
Energy
Volume
ML T
L
ML T
3
22
12
2. (d) : Zeros placed left to the number are never 
significant, therefore the no. of significant figures for the 
numbers 161 cm,  0.161 cm and 0.0161 cm are same, i.e., 3.
3. (c) : According to Avogadro’s hypothesis, ratio of 
the volumes of gases will be equal to the ratio of their no. 
of moles.
So no. of moles = 
Mass
Mol. mass
,
n
w
n
w
n
w
H O CH
2 2 4
2 32 16
= = = ; ;
So, the ratio is or
ww w
23216
1612 : : :: .
4. (a) : C
3
H
8
 + 5O
2
  3CO
2
 + 4H
2
O
      1 vol.  5 vol.        3 vol.         4 vol.
According to the above equation,
1 vol. or 1 litre of propane requires 5 vol. or 5 litres of O
2
 
to burn completely.
5. (b) : Weight of gas = 0.24 g,
Volume of gas = 45 mL = 0.045 litre and density of  
H
2
 = 0.089 g/L
Weight of 45 mL of H
2
 = density × volume
  = 0.089 × 0.045 = 4.005 × 10
–3
 g
Therefore, vapour density
 =
Weight of certain volume of substance
Weight of same volume e of hydrogen
 =
×
=
-
024
4 005 10
59 93
3
.
.
.
6. (c) : If 1 L of one gas contains N molecules, 2 L of any 
gas under the same conditions will contain 2N molecules.
7. (c) : C
2
H
4
 + 3O
2
 ? 2CO
2
 + 2H
2
O
            28 g        96 g
For complete combustion, 
2.8 kg of C
2
H
4
 requires =× ×
96
28
28 10
3
. g
  = 9.6 × 10
3
 g = 9.6 kg of O
2
8. (d) : Average isotopic mass of X
 
=
×+ ×+ ×
++
200 90 1998 202 2
9082
=
++
= ˜
18000 1592 404
100
199 96 . amu 200 amu
9. (a) : A verage atomic mass  
=
×+×
=
19 10 81 11
100
10 81 .
10. (d) : 1 mole of substance = N
A
 atoms
108 g of Ag = N
A
 atoms ? = 1gof Ag atoms
N
A
108
24 g of Mg = N
A
 atoms ? = 1gof Mg atoms
N
A
24
32 g of O
2
 = N
A
 molecules = 2 N
A
 atoms
? = 1gof O atoms
2
N
A
16
 
Hints & Explanations
Page 5


1.3 Properties of Matter and their Measurement
1. The dimensions of pressure are the same as that of
(a) force per unit volume
(b) energy per unit volume
(c) force (d) energy (1995)
1.4 Uncertainty in Measurement
2. Given the numbers : 161 cm, 0.161 cm, 0.0161 cm. The 
number of significant figures for the three numbers 
is
(a) 3, 3 and 4 respectively
(b) 3, 4 and 4 respectively
(c) 3, 4 and 5 respectively
(d) 3, 3 and 3 respectively. (1998)
1.5 Laws of Chemical Combinations
3. Equal masses of H
2
, O
2
 and methane  
have been taken in a container of volume V at 
temperature 27 °C in identical conditions. The ratio 
of the volumes of gases H
2
 : O
2
 : methane would be
(a) 8 : 16 : 1 (b) 16 : 8 : 1
(c) 16 : 1 : 2 (d) 8 : 1 : 2 (2014)
4. What volume of oxygen gas (O
2
) measured at 
0°C and 1 atm, is needed to burn completely 1 L 
of propane gas (C
3
H
8
) measured under the same 
conditions?
(a) 5 L (b) 10 L
(c) 7 L (d) 6 L (2008)
5. 0.24 g of a volatile gas, upon vaporisation, gives 45 mL 
vapour at NTP. What will be the vapour density of 
the substance? (Density of H
2
 = 0.089 g/L)
(a) 95.93 (b) 59.93 
(c) 95.39 (d) 5.993 (1996)
6. The molecular weight of O
2
 and SO
2
 are 32 and 
64 respectively. At 15°C and  150 mmHg pressure, 
one litre of O
2
 contains ‘N’ molecules. The number 
of molecules in two litres of SO
2
 under the same 
conditions of temperature and pressure will be
(a) N/2 (b) N
(c) 2 N (d) 4 N (1990)
7. What is the weight of oxygen required for the 
complete combustion of 2.8 kg of ethylene?
(a) 2.8 kg (b) 6.4 kg
(c) 9.6 kg (d) 96 kg (1989)
1.7 Atomic and Molecular Masses
8. An element, X has the following isotopic composition :
200
X : 90%       
199
X : 8.0%        
202
X : 2.0%
 The weighted average atomic mass of the naturally 
occurring element X is closest to 
(a) 201 amu (b) 202 amu
(c) 199 amu (d) 200 amu (2007)
9. Boron has two stable isotopes, 
10
B(19%) and 
11
B(81%). Calculate average at. wt. of boron in the 
periodic table.
(a) 10.8 (b) 10.2
(c) 11.2 (d) 10.0 (1990)
1.8 Mole Concept and Molar Masses
10. Which one of the followings has maximum number 
of atoms?
(a) 1 g of Ag
(s)
 [Atomic mass of Ag = 108]
(b) 1 g of Mg
(s)
 [Atomic mass of Mg = 24]
(c) 1 g of O
2(g)  
[Atomic mass of O = 16]
(d) 1 g of Li
(s)
 [Atomic mass of Li = 7]
(NEET 2020)
11. In which case is number of molecules of water 
maximum?
(a) 18 mL of water
(b) 0.18 g of water
(c) 0.00224 L of water vapours at 1 atm and 273 K
(d) 10
–3
 mol of water (NEET 2018)
12. Suppose the elements X and Y combine to form two 
compounds XY
2
 and X
3
Y
2
. When 0.1 mole of XY
2
 
weighs 10 g and 0.05 mole of X
3
Y
2
 weighs  9 g, the 
atomic weights of X and Y are
Some Basic Concepts 
of Chemistry
1
CHAPTER
2 NEET-AIPMT Chapterwise Topicwise Solutions Chemistry
(a) 40, 30 (b) 60, 40
(c) 20, 30 (d) 30, 20 (NEET-II 2016)
13. If Avogadro number N
A
, is changed from  
6.022 × 10
23
 mol
–1
 to 6.022 ×  10
20
 mol
–1
, this would 
change
(a) the mass of one mole of carbon
(b) the ratio of chemical species to each other in a 
balanced equation
(c) the ratio of elements to each other in a 
compound 
(d) the definition of mass in units of grams. (2015)
14. The number of water molecules is maximum in
(a) 1.8 gram of water
(b) 18 gram of water
(c) 18 moles of water
(d) 18 molecules of water. (2015)
15. A mixture of gases contains H
2
 and O
2
 gases in the 
ratio of 1 : 4 (w/w). What is the molar ratio of the 
two gases in the mixture?
(a) 16 : 1 (b) 2 : 1
(c) 1 : 4 (d) 4 : 1 (2015, Cancelled)
16. Which has the maximum number of molecules 
among the following?
(a) 44 g CO
2
 (b) 48 g O
3
(c) 8 g H
2
 (d) 64 g SO
2
  
(Mains 2011)
17. The number of atoms in 0.1 mol of a triatomic gas is 
(N
A
 = 6.02 × 10
23
 mol
–1
)
(a) 6.026 × 10
22
  (b) 1.806 × 10
23
(c) 3.600 × 10
23
  (d) 1.800 × 10
22
 (2010)
18. The maximum number of molecules is present in 
(a) 15 L of H
2
 gas at STP
(b) 5 L of N
2
 gas at STP
(c) 0.5 g of H
2
 gas 
(d) 10 g of O
2
 gas. (2004)
19. Which has maximum molecules?
(a) 7 g N
2
 (b) 2 g H
2
(c) 16 g NO
2
 (d) 16 g O
2
 (2002)
20. Specific volume of cylindrical virus particle is  
6.02 × 10
–2
 cc/g whose radius and length are 7 Å and 
10 Å respectively. If N
A
 = 6.02 × 10
23
, find molecular 
weight of virus.
(a) 15.4 kg/mol (b) 1.54 × 10
4
 kg/mol
(c) 3.08 × 10
4
 kg/mol (d) 3.08 × 10
3
 kg/mol
(2001)
21. The number of atoms in 4.25 g of NH
3
 is 
approximately
(a) 4 × 10
23
   (b) 2 × 10
23
(c) 1 × 10
23
   (d) 6 × 10
23
  (1999)
22. Haemoglobin contains 0.334% of iron by weight. The 
molecular weight of haemoglobin is approximately 
67200. The number of iron atoms (Atomic weight of 
Fe is 56) present in one molecule of haemoglobin is
(a) 4 (b) 6
(c) 3 (d) 2 (1998)
23. The number of moles of oxygen in one litre of air 
containing 21% oxygen by volume, under standard 
conditions, is
(a) 0.0093 mol (b) 2.10 mol
(c) 0.186 mol (d) 0.21 mol             (1995)
24. The total number of valence electrons in 4.2 g of N
3
–
 
ion is (N
A
 is the Avogadro’s number)
(a) 2.1 N
A
 (b) 4.2 N
A
(c) 1.6 N
A
 (d) 3.2 N
A
 (1994)
25. The number of gram molecules of oxygen in  
6.02 × 10
24
 CO molecules is
(a) 10 g molecules (b) 5 g molecules
(c) 1 g molecule (d) 0.5 g molecules. 
(1990)
26. Ratio of C
p
 and C
v
 of a gas ‘X’ is 1.4. The number  
of atoms of the gas ‘X’ present in 11.2 litres of it at 
NTP will be
(a) 6.02 × 10
23
  (b) 1.2 × 10
23
(c) 3.01 × 10
23
  (d) 2.01 × 10
23
 (1989)
27. The number of oxygen atoms in 4.4 g of CO
2
 is
(a) 1.2 × 10
23
 (b) 6 × 10
22
(c) 6 × 10
23
 (d) 12 × 10
23 
(1989)
28. 1 cc N
2
O at NTP contains
(a) 
18
224
10
22
.
× atoms
(b) 
602
22400
10
23
.
× molecules
(c) 
132
224
10
23
.
× electrons
 
(d) all of the above. (1988)
1.9 Percentage Composition
29. An organic compound contains carbon, hydrogen 
and oxygen. Its elemental analysis gave C, 38.71% 
and H, 9.67%. The empirical formula of the 
compound would be
(a) CHO (b) CH
4
O
(c) CH
3
O (d) CH
2
O (2008)
30. Percentage of Se in peroxidase anhydrous enzyme 
is 0.5% by weight (at. wt. = 78.4) then minimum 
molecular weight of peroxidase anhydrous enzyme is
(a) 1.568 × 10
4
 (b) 1.568 × 10
3
(c) 15.68 (d) 2.136 × 10
4
        (2001)
3 Some Basic Concepts of Chemistry
31. Which of the following fertilizers has the highest 
nitrogen percentage?
(a) Ammonium sulphate
(b) Calcium cyanamide
(c) Urea
(d) Ammonium nitrate (1993)
1.10 Stoichiometry and Stoichiometric   
  Calculations
32. The number of moles of hydrogen molecules 
required to produce 20 moles of ammonia through 
Haber’s process is 
(a) 40 (b) 10
(c) 20 (d) 30 (NEET 2019)
33. The density of 2 M aqueous solution of NaOH is 
1.28 g/cm
3
. The molality of the solution is [Given 
that molecular mass of NaOH = 40 g mol
–1
]
(a) 1.20 m   (b) 1.56 m
(c) 1.67 m   (d) 1.32 m
(Odisha NEET 2019)
34. A mixture of 2.3 g formic acid and 4.5 g oxalic acid 
is treated with conc. H
2
SO
4
. The evolved gaseous 
mixture is passed through KOH pellets. Weight (in g) 
of the remaining product at STP will be
(a) 1.4 (b) 3.0
(c) 2.8 (d) 4.4 (NEET 2018)
35. What is the mass of the precipitate formed when  
50 mL of 16.9% solution of AgNO
3
 is mixed with  
50 mL of 5.8% NaCl solution?
(Ag = 107.8, N = 14, O = 16, Na = 23, Cl = 35.5) 
(a) 3.5 g (b) 7 g
(c) 14 g (d) 28 g (2015)
36. 20.0 g of a magnesium carbonate sample 
decomposes on heating to give carbon dioxide and 
8.0 g magnesium oxide. What will be the percentage 
purity of magnesium carbonate in the sample?
(At. wt. of Mg = 24)
(a) 96   (b) 60 
(c) 84   (d) 75 (2015)
37. When 22.4 litres of H
2(g)
 is mixed with 11.2 litres 
of Cl
2(g)
, each at STP, the moles of HCl
(g)
 formed is 
equal to
(a) 1 mol of HCl
(g)
 (b) 2 mol of HCl
(g)
(c) 0.5 mol of HCl
(g)
 (d) 1.5 mol of HCl
(g)
(2014)
38. 1.0 g of magnesium is burnt with 0.56 g O
2
 in a 
closed vessel. Which reactant is left in excess and 
how much? (At. wt. Mg = 24, O = 16)
(a) Mg, 0.16 g (b) O
2
, 0.16 g
(c) Mg, 0.44 g (d) O
2
, 0.28 g (2014)
39. 6.02 × 10
20
 molecules of urea are present in 100 mL 
of its solution. The concentration of solution is 
(a) 0.001 M (b) 0.1 M
(c) 0.02 M (d) 0.01 M
(NEET 2013)
40. In an experiment it showed that 10 mL of 0.05 M 
solution of chloride required 10 mL of 0.1 M 
solution of AgNO
3
, which of the following will be 
the formula of the chloride (X stands for the symbol 
of the element other than chlorine)?
(a) X
2
Cl
2
 (b) XCl
2
(c) XCl
4
 (d) X
2
Cl
(Karnataka NEET 2013)
41. 25.3 g of sodium carbonate, Na
2
CO
3
 is dissolved in 
enough water to make 250 mL of solution. If sodium 
carbonate dissociates completely, molar concentration 
of sodium ion, Na
+
 and carbonate ions, CO
3
2–
 are 
respectively
 (Molar mass of Na
2
CO
3
 = 106 g mol
–1
)
(a) 0.955 M and 1.910 M
(b) 1.910 M and 0.955 M
(c) 1.90 M and 1.910 M
(d) 0.477 M and 0.477 M (2010)
42. 10 g of hydrogen and 64 g of oxygen were filled in a 
steel vessel and exploded. Amount of water produced 
in this reaction will be
(a) 3 mol (b) 4 mol
(c) 1 mol (d) 2 mol (2009)
43. How many moles of lead(II) chloride will be formed 
from a reaction between 6.5 g of PbO and 3.2 g HCl?
(a) 0.011 (b) 0.029
(c) 0.044 (d) 0.333 (2008)
44. The mass of carbon anode consumed (giving only 
carbon dioxide) in the production of 270 kg of 
aluminium metal from bauxite by the Hall process is 
(a) 270 kg (b) 540 kg
(c) 90 kg (d) 180 kg
(Atomic mass : Al = 27)   (2005)
45. Molarity of liquid HCl, if density of solution is  
1.17 g/cc is 
(a) 36.5 (b) 18.25
(c) 32.05 (d) 42.10 (2001)
46. Volume of CO
2
 obtained by the complete 
decomposition of 9.85 g of BaCO
3
 is
(a) 2.24 L (b) 1.12 L
(c) 0.84 L (d) 0.56 L (2000)
4 NEET-AIPMT Chapterwise Topicwise Solutions Chemistry
47. In the reaction,
 4NH
3(g)
 + 5O
2(g)
 ? 4NO
(g)
 + 6H
2
O
(l)
 when 1 mole of ammonia and 1 mole of O
2
 are made 
to react to completion
(a) all the oxygen will be consumed
(b) 1.0 mole of NO will be produced
(c) 1.0 mole of H
2
O is produced
(d) all the ammonia will be consumed. (1998)
48. The amount of zinc required to produce 224 mL of 
H
2
 at STP on treatment with dilute H
2
SO
4
 will be
(a) 65 g (b) 0.065 g
(c) 0.65 g (d) 6.5 g (1996)
49. At STP the density of CCl
4
 vapour in g/L will be 
nearest to
(a) 6.87   (b) 3.42
(c) 10.26   (d) 4.57 (1988)
ANSWER KEY
1. (b) 2. (d) 3. (c) 4. (a) 5. (b) 6. (c) 7. (c) 8. (d) 9. (a) 10. (d) 
11. (a) 12. (a) 13. (a) 14. (c) 15. (d) 16. (c) 17. (b) 18. (a) 19. (b) 20. (a) 
21. (d)  22. (a) 23. (a)  24. (c) 25. (b) 26. (a) 27. (a) 28. (d) 29. (c) 30. (a) 
31. (c) 32. (d) 33. (c)  34. (c) 35. (b) 36. (c) 37. (a) 38. (a) 39. (d)  40. (b) 
41. (b) 42. (b) 43. (b) 44. (c) 45. (c) 46. (b) 47. (a) 48. (c) 49. (a)
1. (b) : Pressure=
Force
Area
Therefore, dimensions of pressure =
-
MLT
L
2
2
 = ML
–1
T
–2
 
and dimensions of energy per unit volume 
 
= = =
-
--
Energy
Volume
ML T
L
ML T
3
22
12
2. (d) : Zeros placed left to the number are never 
significant, therefore the no. of significant figures for the 
numbers 161 cm,  0.161 cm and 0.0161 cm are same, i.e., 3.
3. (c) : According to Avogadro’s hypothesis, ratio of 
the volumes of gases will be equal to the ratio of their no. 
of moles.
So no. of moles = 
Mass
Mol. mass
,
n
w
n
w
n
w
H O CH
2 2 4
2 32 16
= = = ; ;
So, the ratio is or
ww w
23216
1612 : : :: .
4. (a) : C
3
H
8
 + 5O
2
  3CO
2
 + 4H
2
O
      1 vol.  5 vol.        3 vol.         4 vol.
According to the above equation,
1 vol. or 1 litre of propane requires 5 vol. or 5 litres of O
2
 
to burn completely.
5. (b) : Weight of gas = 0.24 g,
Volume of gas = 45 mL = 0.045 litre and density of  
H
2
 = 0.089 g/L
Weight of 45 mL of H
2
 = density × volume
  = 0.089 × 0.045 = 4.005 × 10
–3
 g
Therefore, vapour density
 =
Weight of certain volume of substance
Weight of same volume e of hydrogen
 =
×
=
-
024
4 005 10
59 93
3
.
.
.
6. (c) : If 1 L of one gas contains N molecules, 2 L of any 
gas under the same conditions will contain 2N molecules.
7. (c) : C
2
H
4
 + 3O
2
 ? 2CO
2
 + 2H
2
O
            28 g        96 g
For complete combustion, 
2.8 kg of C
2
H
4
 requires =× ×
96
28
28 10
3
. g
  = 9.6 × 10
3
 g = 9.6 kg of O
2
8. (d) : Average isotopic mass of X
 
=
×+ ×+ ×
++
200 90 1998 202 2
9082
=
++
= ˜
18000 1592 404
100
199 96 . amu 200 amu
9. (a) : A verage atomic mass  
=
×+×
=
19 10 81 11
100
10 81 .
10. (d) : 1 mole of substance = N
A
 atoms
108 g of Ag = N
A
 atoms ? = 1gof Ag atoms
N
A
108
24 g of Mg = N
A
 atoms ? = 1gof Mg atoms
N
A
24
32 g of O
2
 = N
A
 molecules = 2 N
A
 atoms
? = 1gof O atoms
2
N
A
16
 
Hints & Explanations
5 Some Basic Concepts of Chemistry
7 g of Li = N
A
 atoms ? = 1gof Li atoms
N
A
7
Therefore, 1 g of Li
(s)
, has maximum number of atoms.
11. (a) : (a) Mass of water = V × d = 18 × 1 = 18 g
Molecules of water = mole × N
A
 = =
18
18
NN
AA
(b) Molecules of water = mole × N
A
 =
018
18
.
N
A
 
               = 10
–2
 N
A
(c) Moles of water = =
-
0 00224
22 4
10
4
.
.
  
 Molecules of water = mole × N
A
 = 10
–4
 N
A
(d) Molecules of water = mole × N
A
 = 10
–3
 N
A
12. (a) : Let atomic weight of element X is x and that of 
element Y is y.
For XY
2
, 
n
w
=
Mol.wt.
 
01
10
2
. =
+ xy
 ?  x + 2y = 
10
01
100
.
= ...(i)
For X
3
Y
2
, n
w
=
Mol.wt.
 
005
9
32
. =
+ xy
 ?+ == 32
9
005
180 xy
.
 ...(ii)
On solving equations (i) and (ii), we get x = 40
40 + 2y = 100 ? 2y = 60 ?  y = 30
13. (a) : Mass of 1 mol (6.022 × 10
23
 atoms) of carbon 
       = 12 g
If Avogadro number is changed to 6.022 × 10
20
 atoms 
then mass of 1 mol of carbon
 =
× ×
×
=×
-
12 6 022 10
6 022 10
12 10
20
23
3
.
.
g
14. (c) : 1.8 gram of water
=
×
×
6 023 10
18
18
23
.
.
 
                                         = 6.023 × 10
22
 molecules
18 gram of water = 6.023 × 10
23
 molecules
18 moles of water = 18 × 6.023 × 10
23
 molecules
15. (d) : Number of moles of H
2
 = 1/2
Number of moles of O
2
 =
4
32
 
Hence, molar ratio= =
1
2
4
32
41 : : 
16. (c) : 8 g H
2
 has 4 moles while the others has 1 mole 
each.
17. (b) : No. of atoms = N
A
 × No. of moles × 3
         = 6.023 × 10
23
 × 0.1 × 3 = 1.806 × 10
23
18. (a) : At STP , 22.4 L = 6.023 × 10
23
 molecules
15 L H
2
=
××
= ×
6 023 10 15
22 4
4 033 10
23
23
.
.
. molecules
5 L N
2
=
××
= ×
6 023 10 5
22 4
1 344 10
23
23
.
.
.
 molecules
2 g H
2
 = 6.023 × 10
23 
molecules
0.5 g H
2
 
=
××
= ×
6 023 10 05
2
1 505 10
23
23
. .
.
 molecules
32 g O
2
 = 6.023 × 10
23 
molecules
10 g of O
2
 
=
××
= ×
6 023 10 10
32
1 882 10
23
23
.
.
 
molecules
 
19. (b) : Number of molecules = moles × N
A
Molecules of N
2
 = 
7
14
 N
A
 = 0.5 N
A
Molecules of H
2
 = N
A
Molecules of NO
2
 = 
16
46
 N
A
 = 0.35 N
A
Molecules of O
2
 = 
16
32
 N
A
 = 0.5 N
A
\ 2 g H
2
 (1 mole H
2
) contains maximum molecules.
20. (a) : Specific volume (vol. of 1 g) of cylindrical virus 
particle = 6.02 × 10
–2
 cc/g
Radius of virus, r = 7 Å = 7 × 10
–8
 cm
Volume of virus = pr
2
l
=× × × ×
- -
22
7
710 1010
82 8
( ) = 154 × 10
–23
 cc
wt. of  one virus particle 
=
Volume (cc)
Specific volume(cc/g)
  
=
×
×
-
-
154 10
60210
23
2
.
g
\ Molecular wt. of virus = wt. of N
A
 particles
 
=
×
×
××
-
-
154 10
60210
60210
23
2
23
.
. g/mol
 = 15400 g/mol = 15.4 kg/mol
21. (d) : 17 g of NH
3
 = 4N
A
 atoms
4.25 g of NH
3
 = ×
4
17
425
N
A
.atoms
  = N
A
 atoms = 6 × 10
23
 atoms
22. (a) : Quantity of iron in one molecule
   =
67200
100
× 0.334 = 224.45 amu
No. of iron atoms in one molecule of haemoglobin 
   
= =
224 45
56
4
.
23. (a) : Volume of oxygen in one litre of air 
   
=× =
21
100
mL 1000 210
Therefore, no. of moles = 
210
22400
= 0.0093 mol
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