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NEET Practice Test - 21 - NEET MCQ


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30 Questions MCQ Test NEET Mock Test Series 2025 - NEET Practice Test - 21

NEET Practice Test - 21 for NEET 2024 is part of NEET Mock Test Series 2025 preparation. The NEET Practice Test - 21 questions and answers have been prepared according to the NEET exam syllabus.The NEET Practice Test - 21 MCQs are made for NEET 2024 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests for NEET Practice Test - 21 below.
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NEET Practice Test - 21 - Question 1
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Among the following pairs of ions, the lower oxidation state in aqueous solution is more stable than the other, in

Detailed Solution for NEET Practice Test - 21 - Question 1
As we move down in groups 13,14 and 15, inertness of ns2 electrons of valence shell increases (inert pair effect). Thus in metals present at the bottom of the groups 13,14, and 15 lower oxidation state becomes more important, viz. Pb (+2 state rather +4), Bi (+3 state rather +5) and Ti (+1 rather than+3).
NEET Practice Test - 21 - Question 2
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The optically inactive compound from the following is:

Detailed Solution for NEET Practice Test - 21 - Question 2
The optically inactive compound must contain achiral carbon atom(s). Option (d) contains achiral carbon atom

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NEET Practice Test - 21 - Question 3
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The correct order of increasing [H3O+] in the following aqueous solutions is

Detailed Solution for NEET Practice Test - 21 - Question 3
H2SO4 is a strong acid hence pH < 7 , or [H]+ >10-7, the aqueous solution of NaCl is neutral hence pH a 7 or [H+] ≈ 10-7. The aqueous solution of NaNO2 will be basic hence pH > 7 or [H+] < 10-7 H2S is a weak acid. Therefore, the correct order will be 0.01 M NaNO2 < 0.01 M NaCl < 0.01 M H2S < 0.01M H2S04
NEET Practice Test - 21 - Question 4
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All form ideal solution except
Detailed Solution for NEET Practice Test - 21 - Question 4
C2H5I and C2H5OH form non-ideal solutions.
NEET Practice Test - 21 - Question 5
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The hybridization of atomic orbitals of nitrogen in NO2+ , NO2- and NH4+ are
Detailed Solution for NEET Practice Test - 21 - Question 5
NO2+ = 1/2 [5 + 0 + 0 - 1] = 2 sp;

NO2- = 1/2 [5 + 0 + 1 - 0] = 3 sp2;

NO4+ = 1/2 [5 + 4 + 0 - 1] = 4 sp3;

NEET Practice Test - 21 - Question 6
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Which of the following has correct for increasing basic strength?

Options

(a) MgO < BeO < CaO < BaO

(b) BeO < MgO < CaO < BaO

(c) BaO < CaO < MgO < BeO

(d) CaO < BaO < BeO < MgO

Detailed Solution for NEET Practice Test - 21 - Question 6
BeO < MgO < CaO < BaO

The basic character of the oxides increases down the group.

Among these BeO is amphoteric.

NEET Practice Test - 21 - Question 7
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Which of the following is commercially known as oxone?
Detailed Solution for NEET Practice Test - 21 - Question 7
(Na2O2 + HCl) is commercially known as ozone and is used for bleaching of delicate fibres.
NEET Practice Test - 21 - Question 8
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The unusual properties of water in the condensed phase (liquid and solid states) are due to the
Detailed Solution for NEET Practice Test - 21 - Question 8
The unusual properties of water in the condensed phase (liquid and solid states) are due to the presence of
NEET Practice Test - 21 - Question 9
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Which one of the following statements concerning lanthanide elements is false?
Detailed Solution for NEET Practice Test - 21 - Question 9
The ionic radii of trivalent lanthanides decreases progressively with increase in atomic number. This decrease is known as lanthanide contraction.
NEET Practice Test - 21 - Question 10
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The hypothetical complex chlorodiaquotriammine cobalt (III) chloride can be represented as
Detailed Solution for NEET Practice Test - 21 - Question 10
Chloro diaquatriammine cobalt (III) chloride is [CoCl (NH3)3 (H2O)2 ] Cl2
NEET Practice Test - 21 - Question 11
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For the compoundsCH3Cl, CH3Br, CH3I and CH3F, the correct order of increasing C-halogen bond length is:
Detailed Solution for NEET Practice Test - 21 - Question 11
The correct order of increasing bond length is CH3F< CH3Cl < CH3Br < CH3I
NEET Practice Test - 21 - Question 12
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The ammonia (NH3) released on quantitative reaction of 0.6 g urea (NH2CONH2) with sodium hydroxide (NaOH) can be neutralized by:
Detailed Solution for NEET Practice Test - 21 - Question 12
1 mol of urea = 2 mol of NH3

60 g of urea = 2 mol of NH3

0.6 g of urea = 2/60 x 0.6mol = 0.02 mol of NH3

mol of NH3 = mol of HCl

∴ mol of HCl = 0.02 mol

⇒ Normality of HC1 = 0.2 N

Volume of HCL = 100 mL

NEET Practice Test - 21 - Question 13
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The INCORRECT statement is :
Detailed Solution for NEET Practice Test - 21 - Question 13

(a) Bronze contains 88-96% Cu and 4-12% Sn.

(b) Cast iron is used to make wrought iron.

(c) German silver contains 50% Cu, 30% Zn & 20% Ni.

(d) Brass contains 70% Cu and 30% Zn

NEET Practice Test - 21 - Question 14
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Acetylenic hydrogens are acidic because
Detailed Solution for NEET Practice Test - 21 - Question 14
The acidity of acetylene or 1 -alkynes can be explained on the basis of molecular orbital concept according to which formation of C — R bond in acetylene involves ip- hybridised carbon atom. Now since s electrons are closer to the nucleus than p electrons, the electrons present in a bond having more s character will be correspondingly more closer to the nucleus.

Thus owing to high s character of the C — FT bond in alkynes (s = 50%), the electrons constituting this bond are more strongly held by the carbon nucleus (i.e. The acetylenic carbon atom or the sp orbital acts as more electronegative species than the sp2- and sp1 with the result the hydrogen present on such a carbon atom (=C — H) can be easily removed as a proton.

NEET Practice Test - 21 - Question 15
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Aqueous solution of group 2 is precipitated by adding Na2CO3, then this precipitate is tested on flame, no light in visible region is observed , this element can be
Detailed Solution for NEET Practice Test - 21 - Question 15
Electrons in Mg due to its small size are tightly bound so they cannot be excited by the flame.
NEET Practice Test - 21 - Question 16
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A reaction at 1 bar is non–spontaneous at low temperature but becomes spontaneous at high temperature. Identify the correct statement about the reaction among the following:
Detailed Solution for NEET Practice Test - 21 - Question 16
∆G = ∆H-T∆S

For a spontaneous reaction ∆G = -ve

which is possible when both ∆H and ∆S are positive at high temperature and hence the reaction becomes spontaneous.

NEET Practice Test - 21 - Question 17
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When CH3Cl and AlCl3 are used in Friedel-Crafts reaction, the electrophile is
Detailed Solution for NEET Practice Test - 21 - Question 17

NEET Practice Test - 21 - Question 18
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The monomer of the polymer;
Detailed Solution for NEET Practice Test - 21 - Question 18
Addition of monomers follows isoprene rule

NEET Practice Test - 21 - Question 19
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The correct statement for the molecule, CsI3 is:
Detailed Solution for NEET Practice Test - 21 - Question 19
Csl3, dissociates as Csl3 → Cs+ + I3-
NEET Practice Test - 21 - Question 20
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Which of the following statements about the advantage of roasting of sulphide ore before reduction is not true?
Detailed Solution for NEET Practice Test - 21 - Question 20
The sulphide ore is roasted to oxide before reduction because the ΔGf° of most of the sulphides are greater than those of CS2 and H2S, therefore neither C nor H can reduce metal sulphide to metal. Further, the standard free energies o f formation o f oxide are much less than those o f SO2. Hence oxidation of metal sulphides to metal oxide is thermodynamically favourable.
NEET Practice Test - 21 - Question 21
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Pollution in large cities can be checked only by:
NEET Practice Test - 21 - Question 22
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Which of the following metal ions will form complexes with the same magnetic moment and geometry irrespective of the nature of ligands?
Detailed Solution for NEET Practice Test - 21 - Question 22
Cu2+ forms complexes with the same magnetic moment and geometry irrespective of the nature of ligand. It can be explained by electronic configuration.

It has 9 electrons in a 3d shell. Hence any incoming ligand whether it is strong or weak will result in the formation of the same geometry (if the number of ligands is same) because any ligand can do nothing with this unpaired e- in 3d shell. Moreover, the complex formed will have the same magnetic moment due to this unpaired e-.

NEET Practice Test - 21 - Question 23
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Enthalpy and entropy change for a chemical reaction are –2.5 × 103 cals and 7.4 cals deg–1 respectively. At 25°C the reaction is:
Detailed Solution for NEET Practice Test - 21 - Question 23
ΔH = -2.5x 103cal

ΔS = 7.4 cal

ΔG = ΔH - TΔS

= -2 .5 x 103 - 298x7.4 = - 4705 .2 Cal.

ΔG = - ive; so process is spontaneous

ΔG = 0, Equilibrium

ΔG = + ive; Non-spontaneous

NEET Practice Test - 21 - Question 24
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One litre of 1 M CuSO4 solution is electrolysed.

After passing 2 F of electricity, molarity of CuSO4 solution will be
Detailed Solution for NEET Practice Test - 21 - Question 24
1 L of 1M CuSO4 = 1 mol of Cu2+

Cu2+ + 2e- → Cu

2 F of electricity will convert dil Cu2+ into Cu, hence [CuSO4] = 0

Thus, (d)

NEET Practice Test - 21 - Question 25
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Which is not correct regarding the adsorption of a gas on the surface of a solid?
Detailed Solution for NEET Practice Test - 21 - Question 25
On increasing temperature adsorption of a gas on the surface of solid decreases. Solid adsorb greater amounts of substances at lower temperature.
NEET Practice Test - 21 - Question 26
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Match the organic compounds in column-I with the Lassaigne’s test results in column-II appropriately:
Detailed Solution for NEET Practice Test - 21 - Question 26
In Lassaigne's test, fusion with sodium takes place and following species formed respectively.

(a) Aniline → CN-

(b) Benzene sulfonic acid →

(c) Thiourea → S2-

Reaction of CN- with hot and acidic solution of FeSO4 leads to formation of Fe4[Fe(CN)6]3 which is blue in colour. It contains iron in both II and III oxidation states.

Reaction of S2- with sodium nitroprusside

Na2S + Na,[Fe(CN)5NO] → Na4[Fe(CN)5NOS] (violet in colour)

Phenoxide ions reacting with FeCl3 give red colour with FeCl3.

NEET Practice Test - 21 - Question 27
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The fraction of total volume occupied by the atoms present in a simple cube is
Detailed Solution for NEET Practice Test - 21 - Question 27
Number of atoms per unit cell = 1

Atoms touch each other along edges. Hence r = a/2 ( r = radius o f atom and a = edge length)

Therefore % fraction

=

= ?/6

= 0.52

NEET Practice Test - 21 - Question 28
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Which of the following may be considered to be an organometallic compound?
Detailed Solution for NEET Practice Test - 21 - Question 28
organometallic compounds are those compounds in which there is a bond which involves metal. In chlorophyll there is bond involving metal Mg
NEET Practice Test - 21 - Question 29
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In the following reaction ‘A ’ is
Detailed Solution for NEET Practice Test - 21 - Question 29

NEET Practice Test - 21 - Question 30
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Which of the following statements is incorrect regarding benzyl chloride?
Detailed Solution for NEET Practice Test - 21 - Question 30
Benzyl chloride (C6H5CH2Cl) is more reactive than vinyl chloride (CH2 = CHCl)
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