Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev

Chemistry Class 12

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JEE : Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev

The document Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev is a part of the JEE Course Chemistry Class 12.
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Q.1. Among statements (I)-(IV), the correct ones are
(I) Decomposition of hydrogen peroxide gives dioxygen.

(II) Like hydrogen peroxide, compounds, such as KClO3, Pb(NO3)2 and NaNO3 when heated liberate dioxygen.
(III) 2-Ethylanthraquinone is useful for the industrial preparation of hydrogen peroxide.
(IV) Hydrogen peroxide is used for the manufacture of sodium perborate.    (2020)
(1) (I), (II), (III) and (IV)
(2) (I), (II) and (III) only
(3) (I), (III) and (IV) only
(4) (I) and (III) only
Ans.
(1)
Option (I): Decomposition of hydrogen peroxide:
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev
Option (II): Decomposition of KClO3, Pb(NO3)2 and NaNO3:
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev
Option (III): 2-Ethylanthraquinone is used for the industrial preparation of H2O2:
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev
Option (IV): H2O2 is used to for the manufacture of sodium perborate.
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev

Q.2. In comparison to the zeolite process for the removal of permanent hardness, the synthetic resins method is    (2020)
(1) Less efficient as it exchanges only anions
(2) More efficient as it can exchange both cations as well as anions
(3) Less efficient as the resins cannot be regenerated
(4) More efficient as it can exchange only cations
Ans.
(2)
Since, in synthetic resin method, both cations and anions can exchange, thus, it if more efficient than zeolite method for removal of permanent hardness of water.

Q.3. Hydrogen has three isotopes (I), (II) and (III). If the number of neutron(s) in (I), (II) and (III) respectively, are (x), (y) and (z), the sum of (x), (y) and (z) is    (2020)
(1) 3
(2) 2
(3) 4
(4) 1
Ans.
(1)
The three isotopes of hydrogen are exist, that is, protium (1H), deuterium (2H) and tritium (3H).
The number of neutrons in isotopes of hydrogen:
1H = 0 neutrons
2H = 1 neutrons
3H = 2 neutrons
Thus, sum of neutrons in isotopes of hydrogen = 0 + 1 + 2 = 3

Q.4. The correct match between Column I and Column II is    (2020)
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev
(1) (a) → (p), (b) → (s), (c) → (r), (d) → (q)
(2) (a) → (r), (b) → (s), (c) → (p), (d) → (q)
(3) (a) → (r), (b) → (p), (c) → (s), (d) → (q)
(4) (a) → (s), (b) → (q), (c) → (p), (d) → (r)
Ans.
(3)
Solution.
The diseases from the deficiency of the following Vitamins are:
A → (r): Riboflavin (Vitamin B2) → Cheilosis (fissuring at corners of mouth and lips).
B → (p): Thiamine (Vitamin B1) → Beri beri (loss of appetite)
C → (s): Pyridoxine (Vitamin B6) → Convulsion (this is a neurological disorder).
D → (q): Ascorbic acid (Vitamin C) → Scurvy (bleeding gums).

Q.5. Which of the following statements is correct?    (2020)
(1) Gluconic acid can form cyclic (acetal/hemiacetal) structure.
(2) Gluconic acid is a dicarboxylic acid.
(3) Gluconic acid is a partial oxidation product of glucose.
(4) Gluconic acid is obtained by oxidation of glucose with HNO3.
Ans.
(3)
On partial oxidation of glucose gluconic acid is formed, and on complete oxidation by HNO3, saccharic acid is formed.
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev

Q.6. Which of the following statement is not true for glucose?    (2020)
(1) Glucose exists in two crystalline forms α and β
(2) Glucose gives Schiff’s test for aldehyde
(3) Glucose reacts with hydroxylamine to form oxime
(4) The pentaacetate of glucose does not react with hydroxylamine to give oxime
Ans
. (2)
Glucose exist as cyclic form, thus, the aldehyde group of glucose does not available for Schiff’s test.
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev

Q.7. Two monomers in maltose are    (2020)
(1) α-D-glucose and β-D-glucose
(2) α-D-glucose and α-D-glucose
(3) α-D-glucose and α-D-Fructose
(4) α-D-glucose and α-D-glucose
Ans. 
(4)
Solution.
The hydrolysis of maltose sugar:
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev

Q.8. A, B and C are three biomolecules. The results of the tests performed on them are given below    (2020)
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev
A, B and C respectively
(1) A = Glucose, B = Fructose, C = Albumin
(2) A = Lactose, B = Glucose, C = Albumin
(3) A = Lactose, B = Glucose, C = Alanine
(4) A = Lactose, B = Fructose, C = Alanine
Ans.
(2)
Carbohydrates do not respond to Biuret test. Lactose do not respond to Barfoed test, since, it is a disaccharide. Glucose responds to both the tests, that is, Molisch’s and Barfoed test. Hence, the given biomolecules are: A = Lactose; B = Glucose; C = Albumin.

Q.9. The number of chiral carbons in chloramphenicol is ______.    (2020)
Ans.
(2)
The structure of chloramphenicol is
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev

Q.10. The number of sp2 hybridized carbons present in “Aspartame” is ________.    (2020)
Ans.
(9)
The structure of aspartame is
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev

Thus, there is total of 9 sp2 hybridized.

Q.11. The number of chiral centres in penicillin is ________.    (2020)
Ans.
(3)
The structure of penicillin is
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev

Q.12. Among the gases (I) – (V), the gases that cause greenhouse effect are    (2020)
(I) CO2
(II) H2O
(III) CFCs
(IV) O2
(V) O3
(1) (I), (II), (III) and (IV)
(2) (I), (II), (III) and (V)
(3) (I) and (IV)
(4) (I), (III), (IV) and (V)
Ans.
(2)
The gases which cause greenhouse effect are CO2, CFCs, H2O and O3. O2 does not cause green-house effect.

Q.13. Biochemical Oxygen Demand (BOD) is the amount of oxygen required (in ppm)    (2020)
(1) For sustaining life in a water body.
(2) By bacteria to break-down organic waste in a certain volume of a water sample.
(3) For the photochemical breakdown of waste present in 1 m3 volume of a water body.
(4) By anaerobic bacteria to breakdown inorganic waste present in a water body
Ans.
(2)
BOD is the oxygen required by bacteria to break down the organic waste in a certain volume of a water sample.

Q.14. Preparation of Bakelite proceeds via reactions    (2020)
(1) Electrophilic addition and dehydration
(2) Condensation and elimination
(3) Electrophilic substitution and dehydration
(4) Nucleophilic addition and dehydration
Ans.
(3)
The reaction involved in preparation of Bakelite polymer is:
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev

Q.15. Which polymer has ‘chiral’ monomer(s)?    (2020)
(1) Neoprene
(2) Buna-N
(3) Nylon-6,6
(4) PHBV
Ans.
(4)
The monomers of PHBV polymer are 3-hydroxybutanoic acid and 3-hydroxypentanoic acid. Both monomers are chiral compounds.
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev

Q.16. The isotopes of hydrogen are:    (2019)
(1) Tritium and protium only
(2) Protium and deuterium only
(3) Protium, deuterium and tritium
(4) Deuterium and tritium only
Ans.
(3)
Hydrogen has three isotopes:
Protium (1H1), deuterium (1H2) and tritium (1H3).

Q.17. The temporary hardness of water is due to:    (2019)
(1) Na2SO4
(2) NaCl
(3) Ca(HCO3)2
(4) CaCl2
Ans. 
(3)
Only bicarbonates cause temporary hardness, whereas chlorides and sulphates cause permanent hardness.

Q.18. The total number of isotopes of hydrogen and number of radioactive isotopes among them, respectively, are:    (2019)
(1) 3 and 1
(2) 3 and 2
(3) 2 and 1
(4) 2 and 0
Ans.
(1)
There are three isotopes of H out of which only tritium is radioactive, which emits low energy β- particles. Its half life is 12.33 years.

Q.19. The chemical nature of hydrogen peroxide is:    (2019)
(1) Oxidising agent in acidic medium, but not in basic medium.
(2) Reducing agent in basic medium, but not in acidic medium.
(3) Oxidising and reducing agent in acidic medium, but not in basic medium.
(4) Oxidising and reducing agent in both acidic and basic medium.
Ans.
(4)
H2O2 acts as oxidising agent as well as reducing agent in both acidic and basic medium.
H2O2 acts as oxidant:
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev

Q.20. The correct statements among (a) to (d) regarding H2 as a fuel are:    (2019)
(a) It produces less pollutants than petrol.
(b) A cylinder of compressed dihydrogen weighs ~ 30 times more than a petrol tank producing the same amount of energy.
(c) Dihydrogen is stored in tanks of metal alloys like NaNi5.
(d) On combustion, values of energy released per gram of liquid dihydrogen and LPG are 50 and 142 kJ, respectively.
(1) (b) and (d) only
(2) (a) and (c) only
(3) (b), (c) and (d) only
(4) (a), (b) and (c) only
Ans. 
(4)
Option (a), (b) and (c) are correct.

Q.21. The hardness of a water sample (in terms of equivalents of CaC03) containing 10-3M CaSO4 is:
(molar mass of CaSO4=136 g mol-1)    (2019)
(1) 10 ppm
(2) 50 ppm
(3) 90 ppm
(4) 100 ppm
Ans. 
(4)
⇒ 10-3 M CaCO3 means 10-3 moles of CaCO3 are present in 1 L
Molar mass of CaCO3 = 40 + 12 + 48 = 100 g/mol
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev
i.e. 100 mg of CaCO3 is present in 1 L solution.
Hardness of water = Number of milligram of CaCO3 per litre of water.
∴ Hardness of water = 100 ppm

Q.22. The volume strength of 1M H2O2 is:
(Molar mass of H2O2 = 34 g mol-1)    (2019)
(1) 5.6
(2) 16.8
(3) 11.35
(4) 22.4
Ans. 
(3)
Volume strength = 11.35 x molarity = 11.35

Q.23. 100 mL of a water sample contains 0.81 g of calcium bicarbonate and 0.73 g of magnesium bicarbonate. The hardness of this water sample expressed in terms of equivalents of CaCO3 is:
(molar mass of calcium bicarbonate is 162 g mol-1 and magnesium bicarboante is 146 g mol-1)    (2019)
(1) 5,000 ppm
(2) 1,000 ppm
(3) 100 ppm
(4) 10,000 ppm

Ans. (4)
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev

Q.24. The strength of 11.2 volume solution of H2O2 is: [Given that molar mass of H = 1 g mol-1 and O = 16 g mol-1]    (2019)
(1) 13.6% 
(2) 3.4%
(3) 34% 
(4) 1.7%
Ans.
(2)
11.2 V strength of H2O2 means,
11.2 L of O2 is liberated at STP.
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev
∴ No. of moles of H2O2 = 1 mol i.e., 1 L of given H2O2 solution has 1 mole of H2O2 (i.e., 34 g)
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev

Q.25. The number of water molecules(s) not coordinated to copper ion directly in CuSO4.5H2O, is:    (2019)
(1)2
(2) 3
(3) 1
(4) 4
Ans.
(3)
In CuSO4.5H2O, four H2O molecules are directly coordinated to the central metal ion while one H2O molecule is hydrogen bonded.

Q.26. The synonym for water gas when used in the production of methanol is:    (2019)
(1) natural gas
(2) fuel gas
(3) laughing gas
(4) syn gas
Ans. 
(4)
When steam is passed over red hot coke, an equimolar mixture of CO and H2 is obtained.
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev
The gaseous mixture thus obtained is called water gas or syn gas (synthesis gas).

Q.27. The correct statements among (a) to (d) are:    (2019)
(a) saline hydrides produce H2 gas when reacted with H2O.
(b) reaction of LiAlH4 with BF3 leads to B2H6.
(c) PH3 and CH4 are electron - rich and electron - precise hydrides, respectively,
(d) HF and CH4 are called as molecular hydrides.

(1) (a), (b), (c) and (d)
(2) (c) and (d) only
(3) (a), (c) and (d) only
(4) (a), (b) and (c) only
Ans.
(4)
(a) Saline hydrides with water produces H2 gas.
(b) 3LiAlH4 + 4BF3 → 2B2H6 + 3LiF + 3AlF3
(c) PH3 is electron rich whereas CH4 is electron precise hydride.
(d) HF and CH4 are molecular hydrides.

Q.28. The temporary hardness of a water sample is due to compound X. Boiling this sample converts X to compound Y. X and Y, respectively, are:    (2019)
(1) Mg (HCO3)2 and Mg(OH)2
(2) Ca (HCO3)2 and Ca(OH)2
(3) Mg (HCO3)2 and MgCO3
(4) Ca(HCO3)2 and CaO
Ans.
(1)
Temporary hardness is caused by bicarbonates of calcium and magnesium. On boiling following changes occurs,
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev   

Q.29. A water sample has ppm level concentration of the following metals: Fe = 0.2; Mn = 5.0; Cu = 3.0; Zn = 5.0. The metal that makes the water sample unsuitable for drinking is:    (2019)
(1) Cu
(2) Mn
(3) Fe 
(4) Zn
Ans.
(2)
The water sample containing Mn = 5 ppm is unsuitable for drinking as the prescribed level for Mn in drinking water is 0.5 ppm.

Q.30. Which of the following conditions in drinking water causes methemoglobinemia?    (2019)
(1) >50 ppm of lead
(2) > 50 ppm of chloride
(3) > 50 ppm of nitrate
(4) > 100 ppm of sulphate
Ans.
(3)
Methemoglobinemia is caused by drinking water which is contaminated with nitrate.

Q.31. The pH of rain water, is approximately:    (2019)
(1) 5.6
(2) 7.5
(3) 7.0
(4) 6.5
Ans.
(1)
pH of rain water is around 5.6.

Q.32. Water filled in two glasses A and B have BOD values of 10 and 20, respectively. The correct statement regarding them, is:    (2019)
(1) B is more polluted than A.
(2) A is suitable for drinking, whereas B is not.
(3) Both A and B are suitable for drinking.
(4) A is more polluted than B.

Ans. (1)
BOD indicates the amount of putrescible organic matter present in water. Therefore, a low BOD is an indicator of good quality water while a high BOD indicates polluted water.

Q.33. The reaction that is NOT involved in the ozone layer depletion mechanism in the stratosphere is:    (2019)
(1) Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev
(2) Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev
(3) Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev
(4) Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev

Ans. (3)
The reaction, CH4 + 2O3 → 3CH2 = O + 3H2O, is not involved in the ozone layer depletion mechanism.

Q.34. The concentration of dissolved oxygen (DO) in cold water can go upto:    (2019)
(1) 14 ppm
(2) 8 ppm
(3) 10 ppm
(4) 16 ppm
Ans.
(3)
Dissolved oxygen (DO) in cold water can reach a concentration upto 10 ppm.

Q.35. Peroxyacetyl nitrate (PAN), an eye irritant, is produced by:    (2019)
(1) Classical smog
(2) Acid rain
(3) Organic waste
(4) Photochemical smog

Ans. (4)
P.A.N is produced by photochemical smog.

Q.36. Taj Mahal is being slowly disfigured and discoloured. This is primarily due to:    (2019)
(1) Global warming
(2) Acid rain
(3) Water pollution
(4) Soil pollution
Ans.
(2)
Acid rain

Q.37. The higher concentration of which gas in air can cause stiffness of flower buds?    (2019)
(1) NO2
(2) CO2
(3) SO2
(4) CO
Ans. 
(3)
High concentration of SO2 leads to stiffness of flower buds.

Q.38. The molecule that has minimum/no role in the formation of photochemical smog, is:    (2019)
(1) N2
(2) CH= O
(3) O3
(4) NO
Ans. 
(1)
NO, O3 and HCHO are responsible for the formation of photochemical smog while N2 has no role in photochemical smog.

Q.39. Water samples with BOD values of 4 ppm and 18 ppm, respectively, are:    (2019)
(1) Clean and Clean
(2) Highly polluted and Clean
(3) Clean and Highly polluted
(4) Highly polluted and Highly polluted
Ans. 
(3)
Clean water would have BOD value < 5 ppm whereas highly polluted water could have BOD value ≥ 17 ppm.

Q.40. The compound that is NOT a common component of photochemical smog is:    (2019)
(1) O3
(2) Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev
(3) CH2 = CHCHO
(4) CF2Cl2
Ans.
(4)
Acrolein, PAN (produced by the oxidation of unburnt hydrocarbons present in the polluted air) and ozone are the main components of photochemical smog. While CF2Cl2 is not a common component of photochemical smog.

Q.41. The upper stratosphere consisting of the ozone layer protects us from the sun’s radiation that falls in the wavelength region    (2019)
(1) 200-315 nm
(2) 400-550 nm
(3) 0.8-1.5 nm
(4) 600-750 nm
Ans.
(1)
Wavelength range lies in 200 nm - 315 nm (U.V light)

Q.42. Which is wrong with respect to our responsibility as a human being to protect our environment?    (2019)
(1) Restricting the use of vehicles
(2) Avoiding the use of floodlighted facilities
(3) Setting up compost tin in gardens.
(4) Using plastic bags.
Ans.
(4)
Use of plastic bags is hazardous to our environment

Q.43. Assertion : Ozone is destroyed by CFCs in the upper stratosphere.
Reason : Ozone holes increase the amount of UV radiation reaching the earth.    (2019)
(1) Assertion and reason are incorrect.
(2) Assertion and reason are both correct, and the reason is the correct explanation for the assertion.
(3) Assertion and reason are correct, but the reason is not the explanation for the assertion.
(4) Assertion is false, but the reason is correct.
Ans. 
(3)
CFC’s are responsible for depletion of ozone layer
Previous year Questions (2016-20) - Carbohydrates, Amino Acids & Polymers - (Part - 1) Notes | EduRev
Due to depletion of ozone layer more UV radiation filters into troposphere.

Q.44. The maximum prescribed concentration of copper in drinking water is:    (2019)
(1) 5 ppm
(2) 0.05 ppm
(3) 0.5 ppm
(4) 3 ppm
Ans.
(4)
Maximum prescribed concentration of Cu in drinking water is 3 ppm.

Q.45. Excessive release of CO2 into the atmosphere results in:    (2019)
(1) global warming
(2) polar vortex
(3) formation of smog
(4) depletion of ozone
Ans.
(1)
Global warming is caused by the emission of green house gases. 72% of the totally emitted green house gases is CO2. Therefore, excessive release of CO2 is the main cause of global warming.

Q.46. The layer of atmosphere between 10 km to 50 km above the sea level is called as:    (2019)
(1) troposphere
(2) thermosphere
(3) stratosphere
(4) mesosphere
Ans. 
(3)
Stratosphere lies between 10-50 km above sea level.

Q.47. The regions of the atmosphere, where clouds are formed and where we live, respectively, are:    (2019)
(1) Troposphere and Stratosphere
(2) Stratosphere and Troposphere
(3) Troposphere and Troposphere
(4) Stratosphere and Stratosphere
Ans.
(3)
The lowest region of atmosphere in which human beings live and clouds form is known as troposphere. It extends up to a height of 10 km from sea level.

Q.48. Air pollution that occurs in sunlight is:    (2019)
(1) reducing smog
(2) acid rain
(3) oxidizing smog
(4) fog
Ans. 
(3)
Air pollution caused by sunlight is photochemical smog also knows as oxidising smog.

Q.49. The correct set of species responsible for the photochemical smog is:    (2019)
(1) N2, NO2 and hydrocarbons
(2) CO2, NO2, SO2 and hydrocarbons
(3) NO, NO2, O3 and hydrocarbons
(4) N2, O2, O3 and hydrocarbons
Ans. 
(3)
Photochemical smog contains oxides of nitrogen, ozone and hydrocarbons. It is also called oxidation smog.

Q.50. The primary pollutant that leads to photochemical smog is:    (2019)
(1) acrolein
(2) nitrogen oxides
(3) ozone
(4) sulphur dioxide
Ans.
(2)
In photochemical smog, NO2 and hydrocarbons are primary pollutants whereas ozone and acrolein are secondary pollutants.

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