Chapter 3 Electrochemistry MCQs for Class 12 Chemistry

Chapter 3 Electrochemistry MCQs for Class 12 Chemistry

Here students can practice Chapter 3 Electrochemistry MCQs for Class 12 Chemistry. All the MCQs are divided into several sub-pages. Each page has 40 MCQs, for the next page just scroll down and click on the buttons. Also you can practice Class 12 Chemistry MCQs (Multiple Choice Questions) for other units.

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Q 1.: How is electrical conductance of a conductor related with length and area of cross-section of the conductor ?

(A) G = l . a . k–1

(B) G = l . k . a–1

(C) G = k . a . l–1

(D) G = l . k . a–2

Option – C

Q 2.: At 25 0C the molar conductance of 0.007 M hydrofluoric acid is 150 mho cm2 mol –1 and its molar conductivity is 500 mho cm2 mol –1. The value of the dissociation constant of the acid at given concentration at 25 0C is :

(A) 9 × 10–4 M

(B) 7 × 10–4 M

(C) 9 × 10–3 M

(D) 7 × 10–5 M

Option – A

Q 3.: Which one of the following has the highest molar conductivity ?

(A) diamminedichloroplatinum(II)

(B) Potassium hexacyanoferrate(II)

(C) hexaaquachromium(III) chloride

(D) Potassium hexacyanoferrate(III)

Option – B

Q 4.: An increase in equivalent conductance of a strong electrolyte with a dilution is mainly due to

(A) Increase in number of ions

(B) Increase in ionic mobility of ions

(C) 100% ionization of electrolyte at normal dilution

(D) Increase in both (i.e. number of ions and ionic mobility of ion.)

Option – B

Q 5.: Read the following statement and predict the corresponding law. “At infinite dilution when dissociation is complete each ion makes a definite contribution towards total equivalent conductance of the electrolyte irrespective of the nature of the ion”.

(A) Ostwald’s dilution law

(B) Ohm’s law

(C) Faraday’s law

(D) Kohlrausch’s law

Option – D

Q 6.: Which one of the following solutions will have the highest conductivity ?

(A) 0.1 M CH3COOH

(B) 0.1 M KNO3

(C) 0.1 M NaCl

(D) 0.1 M HCl

Option – C

Q 7.: The formal potential of Fe+3/Fe+2 in a sulphuric acid and phosphoric acid mixture (E0 = +0.16 V) is much lower than the standard potential (E0 = +0.77 V). This is due to

(A) Formation of the species [FeHPO4]+1

(B) Lowering of potential upon complexation

(C) Formation of species [FeSO4]+1

(D) High acidity of the medium

Option – A

Q 8.: The emf of a galvanic cell, with reduction electrode potential of zinc = ― 0.76 V and that of copper = 0.34 V, is

(A) 0.76 V

(B) 1.6 V

(C) 1.1 V

(D) 0.34 V

Option – C

Q 9.: Lithium occupies higher position in the electrochemical series of metals as compared to copper since,

(A) The standard reduction potential of Cu+2/Cu is lower than that of Li+1/Li.

(B) The standard reduction potential of Li+1/Li is lower than that of Cu+2/Cu.

(C) The standard oxidation potential of Li+1/Li is lower than that of Cu+2/Cu.

(D) Lithium is smaller in size as compared to copper

Option – B

Q 10.: Aluminium displaces hydrogen from acids, but copper does not. A galvanic cell prepared by combining Cu/Cu+2 and Al/Al+3 has an emf of 2.0 V at 298 K. If the potential of copper electrode is +0.34 V, that of aluminium electrode is

(A) +2.34 V

(B) +1.66 V

(C) ―2.34 V

(D) ―1.66 V

Option – D

Q 11.: On passing 3 ampere of electricity for 50 minutes, 1.8 gram of metal deposits. equivalent mass of metal is

(A) 9.3

(B) 19.3

(C) 38.3

(D) 39.9

Option – B

Q 12.: When same quantity of electricity is passed for half an hour the amount of copper and chromium deposited are respectively 0.375 gram and 0.30 gram. Ratio of electrochemical equivalent of copper and chromium is.

(A) 0.8

(B) 1.25

(C) 2.5

(D) 1.62

Option – B

Q 13.: On the basis of E0 values the strongest oxidising agent is :

[Fe(CN)6]–4  →  [Fe(CN)6]–3  + e-  ; E0 = 0.35 V

Fe+2   →  Fe+3  + e-  ; E0 = 0.77 V

(A) [Fe(CN)6]–4 

(B) Fe+2

(C) Fe+3

(D) [Fe(CN)6]–3 

Option – C

Q 14.: Cu+(aq) is unstable in solution and undergoes simultaneous oxidation and reduction, according to the reaction,

               2Cu+1(aq)  ⇄  Cu+2(aq)  + Cu(s)

Choose the correct E0 for the above reaction if, E0 (Cu+2/Cu) = +0.34 V   ;  E0 (Cu+2/Cu+1) = +0.15 V

(A) +0.49 V

(B) +0.34 V

(C) 0.49 V

(D) 0.34 V

Option – B

Q 15.: The equilibrium constant for the following redox reaction at 298 K is 1 × 108.

2Fe+3(aq)  +  2I–1(aq)   ⇄  2Fe+2(aq)  +  I2 (s)

If the standard reduction potential of iodine (I2/ I–1) is +0.54 V, what is the standard reduction potential of Fe+3/Fe+2 ?

(A) +0.077 V

(B) +1.006 

(C) +0.652

(D) 1.006

Option – A

Q 16.: Zn(s) + Cl2 (1 atm)  → Zn+2 + 2Cl–1 ; E0cell of the cell is 2.12 V. To increase E

(A) [Zn +2] should be decreased

(B) [Zn +2] should be increased

(C) [Cl –1] should be decreased

(D) Pressure of Cl2 should be decreased

Option – A

Q 17.: Hydrogen gas is not liberated when the following metals added to dil. HCl

(A) Zn

(B) Mg

(C) Sn

(D) Ag

Option – D

Q 18.: In the silver plating of copper, K[Ag(CN)2] is used instead of AgNO3. The reason is

(A) A thin layer of Ag is formed on Cu

(B) More voltage is required

(C) Less availability of Ag+1 ions, as Cu cannot displaced Ag from [Ag(CN)2]–1 ion.

(D) Ag+1 ions are completely removed form solution

Option – C

Q 19.: Assertion (A) : E0 for Mn+3/Mn+2 is more positive than Cr+3/Cr+2.

Reason (R) : The third ionisation energy of Mn is larger than that of Cr.

(A) Both A and R are correct and R is the correct explanation of A

(B) Both A and R are correct but R is not the correct explanation of A

(C) A is correct but R is incorrect

(D) Both A and R are incorrect

Option – B

Q 20.: During electrochemical process

(A) Gibbs free energy decreases

(B) Gibbs free energy increases

(C) Gibbs free energy remain constant

(D) Cannot be predicted

Option – A

Q 21.: Which will reduce zinc oxide to zinc ?

(A) Cu

(B) Pb

(C) Mg

(D) Fe

Option – C

Q 22.:  Reduction potentials of A, B, C and D are 0.8 V, 0.79 V, 0.34 V and 0.21 V respectively. Which element displaces all the other three elements ?

(A) A

(B) B

(C) C

(D) D

Option – D

Q 23.: The standard emf of Daniell cell is 1.10 V. The maximum electrical work obtained from the cell is :

(A) 175.4 kJ

(B) 350.8 kJ

(C) 106.15 kJ

(D) 212.3 kJ

Option – D

Q 24.:  If hydrogen electrode dipped in two solutions of pH = 3 and pH = 6 and salt bridge is connected, the emf of resulting cell is

(A) 0.33

(B) 0.128

(C) 0.177

(D) 0.986

Option – C

Q 25.: Molar conductivities at infinite dilution of NaCl, HCl and CH3COONa are 126.4, 425.9 and 91.0 S cm2 mol–1 respectively. The molar conductivity for CH3COOH will be

(A) 390.5 S cm2 mol–1

(B) 425.5 S cm2 mol–1

(C) 180.5 S cm2 mol–1

(D) 290.85 S cm2 mol–1

Option – A

Q 26.: At 18 0C, the conductance of H+1 and CH3COO–1 at infinite dilution are 315 and 35 mho cm2 eq–1 respectively. The equivalent conductivity of CH3COOH at infinite dilution is ___________

(A) 380 mho cm2 eq–1

(B) 350 mho cm2 eq–1

(C) 280 mho cm2 eq–1

(D) 30 mho cm2 eq–1

Option – B

Q 27.: Conductivity of 0.01 M NaCl solution is 0.00147 ohm–1 cm–1. What happens to this conductivity, if extra 100 mL of H2O will be added to the above solution ?  

(A) Remain unchanged

(B) First increases and then decreases

(C) Increases

(D) Decreases

Option – D

Q 28.: The compound exhibiting maximum value of equivalent conductance in a fused state is

(A) SrCl2

(B) CaCl2

(C) MgCl2

(D) BeCl2

Option – A

Q 29.: Assertion (A) : According to Kohlrausch’s law the molar conductivity of a strong electrolyte at infinite dilution is sum of molar conductivity of its ions.

Reason (R) : The current carried by cation and anion is always equal

(A) Both A and R are correct and R is the correct explanation of A

(B) Both A and R are correct but R is not the correct explanation of A

(C) A is correct but R is incorrect

(D) Both A and R are incorrect

Option – C

Q 30.: The electrolyte [Co(NH3)5Cl]Cl2 is which of the following type ?

(A) 1 : 3

(B) 2 : 3

(C) 1 : 1

(D) 1 : 2

Option – D

Q 31.: The specific conductance (k) of an electrolyte of 0.1 N concentration is related to equivalent conductance (𝝀) by the following formula

(A) 𝝀 = k

(B) 𝝀 = 10 k

(C) 𝝀 = 100 k

(D) 𝝀 = 1000 k

Option – D

Q 32.: Which of the following is not a non-electrolyte ?

(A) Acetic acid

(B) Glucose

(C) Ethanol

(D) Urea

Option – A

Q 33.: Given, E0 for Cr+3/Cr = 0.72 V and Fe+2/Fe = 0.42 V. The potential for the cell

Cr | Cr+3(0.1M) || Fe+2(0.01M) | Fe, is:

(A) +0.26

(B) +0.24

(C) +0.3

(D) +0.4

Option – C

Q 34.: The standard emf for the given cell reaction is 1.10 V at 25 0C,

Zn + Cu+2  →  Cu + Zn+2

The emf for the cell reaction , when 0.1 M Cu+2 and 0.1 M Zn+2 solutions are used at 25 0C.

(A) +1.42

(B) +1.10

(C) +0.35

(D) +0.48

Option – B

Q 35.:  The equilibrium constant of the reaction,

Cu  +  2Ag+1  →  Cu+2  +  2Ag ; at 298 K is:  (Given, E0cell = +0.46 V)

(A) antilog 13.8

(B) antilog 12.6

(C) antilog 16.2

(D) antilog 15.6

Option – D

Q 36.: The electrode potentials for the reactions,

Cu+2(aq) + e-  →  Cu+1 

 Cu+1(aq) + e-  →  Cu  

are +0.15 V and  +0.50 V respectively. The value of E0 (Cu+2|Cu) will be

(A) +0.343 V

(B) +0.325 V

(C) +0.381 V

(D) +0.65 V

Option – B

Q 37.: Standard electrode potential for Sn+4|Sn+2 couple is +0.15 V and that for the Cr+3|Cr couple is 0.74 V. These two  couples in their standard state are connected to make a cell. The cell potential will be

(A) +1.83 V

(B) +1.19 V

(C) +0.89 V

(D) +0.18 V

Option – C

Q 38.: The standard emf of a galvanic cell involving 2 moles of electrons in its redox reaction is 0.59 V. The equilibrium constant for the redox reaction of the cell is :

(A) 1020

(B) 1015

(C) 1010

(D) 105

Option – A

Q 39.:  E1, E2 and E3 are the emf of the following three galvanic cells respectively.

I.  Zn | Zn+2(0.1 M) || Cu+2(1 M) | Cu

II.  Zn | Zn+2(1 M) || Cu+2(1 M) | Cu

III.  Zn | Zn+2(1 M) || Cu+2(0.1 M) | Cu

Which one of the following is true ?

(A) E2 > E1 > E3

(B) E1 > E2 > E3

(C) E3 > E2 > E1

(D) E3 > E1 > E2

Option – B

Q 40.: For the reduction of silver ions with copper metal, the standard cell potential was found to be +0.46 V at 25 0C. The value of standard Gibb’s energy will be:  (F = 96500 C)

(A) 98.0 J

(B) 98.0 kJ

(C) 89.0 J

(D) 89.0 kJ

Option – D


We hope that these Chapter 3 Electrochemistry MCQs for Class 12 Chemistry helped you in learning new concepts. All questions are based on NCERT syllabus and some of them have been asked in various competitive exams. You can go to the next pages to practice more for Chapter 3 Electrochemistry MCQs for Class 12 Chemistry, click on the question range given above.

Also you can practice Class 12 Chemistry MCQs (Multiple Choice Questions) for other units.