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Free download in PDF CBSE Class 12 Chemistry Objective Type Questions & Answers. Here Gkseries provide Chemistry Solve Questions and Answers for CBSE Class 12 Students.
21
An unripe mango placed in a concentrated salt solution to prepare pickle, shrivels because _________ .
A
it gains water due to osmosis.
B
it loses water due to reverse osmosis.
C
it gains water due to reverse osmosis.
D
it loses water due to osmosis.
View Answer
Answer: it loses water due to reverse osmosis.
22
In comparison to a 0.01 M solution of glucose, the depression in freezing point of a 0.01 M MgCl2 solution is _________ .
A
the same
B
about twice
C
about three times
D
about six times
View Answer
Answer: about three times
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23
Which of the following aqueous solutions should have the highest boiling point?
A
1.0 M NaOH
B
1.0 M Na2SO4
C
1.0 M NH4NO3
D
1.0 M KNO3
View Answer
24
Considering the formation, breaking and strength of hydrogen bond, predict which of the following mixtures will show a positive deviation from Raoult’s law?
A
Methanol and acetone.
B
Phenol and aniline.
C
Chloroform and acetone.
D
Nitric acid and water.
View Answer
Answer: Methanol and acetone.
25
Low concentration of oxygen in the blood and tissues of people living at high altitude is due to _________ .
A
low temperature
B
low atmospheric pressure
C
high atmospheric pressure
D
both low temperature and high atmospheric pressure
View Answer
Answer: low atmospheric pressure
26
The number of moles of NaCl in 3 litres of 3M solution is
View Answer
27
The molality of pure water is
A
60.5
B
55.5
C
50.5
D
18
View Answer
28
If E°Fe2+/Fe = -0.441 V and E°Fe2+/Fe2+ = 0.771 V, the standard EMF of the reaction,
Fe + 2Fe3+ → 3Fe2+ will be
A
1.212 V
B
1.653 V
C
0.111 V
D
0.330 V
View Answer
29
The reaction, 3ClO– (aq) → ClO3 (aq) + 2Cl– (aq) is an example of
A
Oxidation reaction
B
Reduction reaction
C
Disproportionation reaction
D
Decomposition reaction
View Answer
Answer: Disproportionation reaction
30
NH4NC>3 is used in salt bridge because
A
it forms a jelly like material with agar-agar.
B
it is a weak electrolyte.
C
it is a good conductor of electricity.
D
the transport number of NH4+ and NO3– ions are almost equal.
View Answer
Answer: the transport number of NH4+ and NO3– ions are almost equal.
31
limiting molar conductivity of Ca2+ and Cl– are 119.0 and 76.3 S cm2 mol-1, then the value of limiting molar conductivity of CaCl2 will be
A
195.3 S cm2 mol-1
B
271.6 S cm2 mol-1
C
43.3 S cm2 mol-1
D
314.3 S cm2 mol-1.
View Answer
Answer: 271.6 S cm2 mol-1
32
The charge required for the reduction of 1 mol of MnO2– to MnO2 is
View Answer
33
Λ of M/32 solution of weak acid is 8 S cm2 mol-1 and limiting molar conductivity is 400 S cm2 mol1. Ka for acid is
A
1.25 × 10-6
B
6.25× 10-4
C
1.25 × 10-4
D
1.25 × 10-5
View Answer
34
While charging the lead storage battery _________ .
A
PbSO4 anode is reduced to Pb.
B
PbSO4 cathode is reduced to Pb.
C
PbSO4 cathode is oxidised to Pb.
D
PbSO4 anode is oxidised to PbO2.
View Answer
Answer: PbSO4 anode is reduced to Pb.
35
A conductivity cell containing electrodes made up of
A
Gold
B
Silver
C
Platinised platinum
D
Copper
View Answer
Answer: Platinised platinum
36
Ag+(aq) + e– → Ag(s) E° = + 0.80 V
Fe2+(aq)+ + 2e– → Fe(s) E° = – 0.44 V
What is emf of
Fe(s) + 2Ag+(aq) → Fe2+(aq) + 2Ag(s)
A
1.16 V
B
1.24 V
C
2.04 V
D
-1.16 V
View Answer
37
A new galvanic cell of E^u more than E°dl of Daniel cell is connected to Daniel cell in a manner that new cell gives electrons to cathode, what will happen
A
Ecell will increase
B
Ecell will decrease
C
No change will take place
D
Daniel cell will work as electrolytic cell where Zn will be deposite on zinc rod and copper will dissolve from copper rod.
View Answer
Answer: Ecell will decrease
38
The emf of the cell:
Ni / Ni2+ (1.0 M) // Au3+ (1.0 M) / Au (E° = -0.25 V for Ni2+/Ni; E° = 1.5 V for Au3+/Au) is
A
1.25 V
B
-1.25 V
C
1.75 V
D
2.0 V
View Answer
39
The half life period of first order reaction is 1386 seconds. The specific rate constant of the reaction is
A
0.5 × 10-3 s-1
B
5.0 × 10-3 s-1
C
0.5 × 10-2 s-1
D
5.0 × 10-2 s-1
View Answer
40
The rate constant of a reaction A → B is 0.6 × 103 mole per second. If the concentration of [A] is 5 M, then what will be concentration of [B] after 20 months?
A
3.60 M
B
0.36 M
C
0.72 M
D
None of these
View Answer
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