Friday, 29 January 2021

CBSE Class 12 Chemistry - MCQ and Online Tests - Unit 3 - Electrochemistry

CBSE Class 12 Chemistry – MCQ and Online Tests – Unit 3 – Electrochemistry

Every year CBSE conducts board exams for 12th standard. These exams are very competitive to all the students. So our website provides online tests for all the 12th subjects. These tests are also very effective and useful for those who preparing for competitive exams like NEET, JEE, CA etc. It can boost their preparation level and confidence level by attempting these chapter wise online tests.

These online tests are based on latest CBSE Class 12 syllabus. While attempting these our students can identify the weak lessons and continuously practice those lessons for attaining high marks. It also helps to revise the NCERT textbooks thoroughly.


 

CBSE Class 12 Chemistry – MCQ and Online Tests – Unit 3 – Electrochemistry

Question 1.
Molar conductivity of 0.15 M solution of KCl at 298 K, if its conductivity of 0.0152 S cm-1 w ill be
(a) 124 Ω-1 cm² mol-1
(b) 204 Ω-1 cm² mol-1
(c) 101 Ω-1 cm² mol-1
(d) 300 Ω-1 cm² mol-1

Answer

Answer: (c) 101 Ω-1 cm² mol-1


Question 2.
How much time is required to deposit 1 × 10-3 cm thick layer of silver (density of 1.05 g cm-3) on a surface of area 100 cm² by passing a current of 5 A through AgNO3 solution?
(a) 125 s
(b) 115 s
(c) 18.7 s
(d) 27.25 s

Answer

Answer: (c) 18.7 s


Question 3.
Electrical conductance through metals is called metallic or electronic conductance and is due to the movement of electrons. The electronic conductance depends on
(a) the nature and structure of the metal
(b) the number of valence electrons per atom
(c) change in temperature
(d) all of these

Answer

Answer: (d) all of these


Question 4.
The standard electrode potentials for the half cell reactions are:
Zn → Zn2-– 2e E° = 0.76 V
Fe → Fe2- + 2 E° = -0.41 V
The emf of the cell reaction
Fe2- + Zn → Zn2- + Fe is
(a) -0.35 V
(b) +0.35 V
(c) -1.17 V
(d) +1.17 V

Answer

Answer: (b) +0.35 V


Question 5.
The specific conductivity of N/10 KCl solution at 20°C is 0.0212 ohm-1 cm-1 and the resistance of the cell containing this solution at 20°C is 55 ohm. The cell constant is
(a) 3.324 cm-1
(b) 1.166 cm-1
(c) 2.372 cm-1
(d) 3.682 cm-1

Answer

Answer: (b) 1.166 cm-1


Question 6.
Faraday’s law of electrolysis is related to
(a) Atomic number of cation
(b) Speed of cation
(c) Speed of anion
(d) Equivalent weight of electrolyte

Answer

Answer: (d) Equivalent weight of electrolyte


Question 7.
If 96500 coulomb electricity is passed through CuSO4 solution, it will liberate
(a) 63.5 gm of Cu
(b) 31.76 gm of Cu
(c) 96500 gm of Cu
(d) 100 gm of Cu

Answer

Answer: (b) 31.76 gm of Cu


Question 8.
The molar conductivity is maximum for the solution of concentration
(a) 0.004 M
(b) 0.002 M
(c) 0.005 M
(d) 0.001 M

Answer

Answer: (d) 0.001 M


Question 9.
How long would it take to deposit 50 g of Al from an electrolytic cell containing Al2O3 using a current of 105 ampere?
(a) 1.54 h
(b) 1.42 h
(c) 1.32 h
(d) 2.15 h

Answer

Answer: (b) 1.42 h


Question 10.
For a certain redox reaction, E° is positive. This means that
(a) ΔG° is positive, K is greater than 1
(b) ΔG° is positive, K is less than 1
(c) ΔG° is negative, K is greater than 1
(d) ΔG° is negative, K is less than 1

Answer

Answer: (c) ΔG° is negative, K is greater than 1


Question 11.
The charge required for reducing 1 mole of MnO\(_{4}^{-}\) to Mn2- is
(a) 1.93 × 105 C
(b) 2.895 × 105 C
(c) 4.28 × 105 C
(d) 4.825 × 105 C

Answer

Answer: (d) 4.825 × 105 C


Question 12.
Units of the properties measured are given below. Which of the properties has been not matched correctly?
(a) Molar conductance = Sm2 mol-1
(b) Cell constant = m-1
(c) Specific conductance of = S m²
(d) Equivalence conductance = S m² (g eq)-1

Answer

Answer: (c) Specific conductance of = S m²


Question 13.
If a current of 1.5 ampere flows through a metallic wire for 3 hours, then how many electrons would flow through the wire?
(a) 2.25 × 1022 electrons
(b) 1.13 × 1023 electrons
(c) 1.01 × 1023 electrons
(d) 4.5 × 1023 electrons

Answer

Answer: (c) 1.01 × 1023 electrons


Question 14.
Which of the following is a secondary cell?
(a) Leclanche cell
(b) Lead storage battery
(c) Concentration cell
(d) All of these

Answer

Answer: (b) Lead storage battery


Question 15.
How many coulombs of electricity is required to reduce 1 mole of Cr2O\(_{7}^{2-}\) in acidic medium?
(a) 4 × 96500 C
(b) 6 × 96500 C
(c) 2 × 96500 C
(d) 1 × 96500 C

Answer

Answer: (b) 6 × 96500 C


Question 16.
Fused NaCl on electrolysis gives ………….. on cathode.
(a) Chlroine
(b) Sodium
(c) Sodium amalgam
(d) Hydrogen

Answer

Answer: (b) Sodium


Question 17.
A current of 1.40 ampere is passed through 500 mL of 0.180 M solution of zinc sulphate for 200 seconds. What will be the molarity of Zn2+ions after deposition of zinc?
(a) 0.154 M
(b) 0.177 M
(c) 2 M
(d) 0.180 M

Answer

Answer: (b) 0.177 M


Question 18.
How much electricity in in terms of Faraday is required to produce 100 g of Ca from molten CaCl2?
(a) 1F
(b) 2F
(c) 3F
(d) 5F

Answer

Answer: (d) 5F


Question 19.
Equilibrium constant K is related to E\(_{cell}^{0}\) and not E\(_{cell}\) because
(a) E\(_{cell}^{0}\) is easier to measure than E\(_{cell}\)
(b) E\(_{cell}\) becomes zero at equilibrium point but E\(_{cell}^{0}\) remains constant under all conditions
(c) at a given temperature, E\(_{cell}\) changes hence value of K can’t be measured
(d) any of the terms E\(_{cell}\) or E\(_{cell}^{0}\) can be used

Answer

Answer: (b) E\(_{cell}\) becomes zero at equilibrium point but E\(_{cell}^{0}\) remains constant under all conditions


Question 20.
Cell reaction is spontaneous, when
(a) E\(_{red}^{0}\) is negative
(b) ΔG° is negative
(c) E\(_{oxid}^{0}\) is Positive
(d) ΔG° is positive

Answer

Answer: (b) ΔG° is negative


 

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