All In One ISC Chemistry Class 12>Chapter 3 - Electrochemistry>Chapter Practice>Q 21

MEDIUM

12th ICSE

IMPORTANT

Earn 100

Why does a cell stops working after sometime?

Important Questions on Electrochemistry

MEDIUM

12th ICSE

IMPORTANT

All In One ISC Chemistry Class 12>Chapter 3 - Electrochemistry>Chapter Practice>Q 22

Write the Nernst equation and emf of the following cell at $298 K$ : $Fe (s) | {Fe}^{2 +} (0.001 M) ∥ H^{+} (1 M) | H_{2} (g) (1 bar) | Pt$ .

Use

E °_{({Fe}^{2 +} Fe)} = 0.44 V

HARD

12th ICSE

IMPORTANT

All In One ISC Chemistry Class 12>Chapter 3 - Electrochemistry>Chapter Practice>Q 23

The potential for the cell below is found to be

0.25 V

.

Pt (s) H_{2} (g) | H^{+} (aq), (1 mol / L) | | {Cu}^{2 +}

(aq,

C mol / L

)

| Cu (s)

. What is the value of

C

?

MEDIUM

12th ICSE

IMPORTANT

All In One ISC Chemistry Class 12>Chapter 3 - Electrochemistry>Chapter Practice>Q 24

Why does zinc react with dilute sulphuric acid but copper does not?

EASY

12th ICSE

IMPORTANT

All In One ISC Chemistry Class 12>Chapter 3 - Electrochemistry>Chapter Practice>Q 24

Why it is not possible to measure the single electrode potential?

MEDIUM

12th ICSE

IMPORTANT

All In One ISC Chemistry Class 12>Chapter 3 - Electrochemistry>Chapter Practice>Q 25

The emf of a cell corresponding to the reaction,

Zn (s) + 2 H^{+} (aq) \to {Zn}^{2 +} (0.1 M) + H_{2} (g), (1 atm)

is

0.28 V

at

25^{°} C

.
Write the half-cell reactions and calculate the

pH

of the solution at the hydrogen electrode.

{E^{°}}_{{Zn}^{2 +} / Zn} = - 0.76 V, E^{°}_{H^{+} / H_{2}} = 0

.

HARD

12th ICSE

IMPORTANT

All In One ISC Chemistry Class 12>Chapter 3 - Electrochemistry>Chapter Practice>Q 26

Find the equilibrium constant for the reaction,

{Cu}^{2 +} + {In}^{2 +} ⇌ {Cu}^{+} + {In}^{3 +}

. Given that,

E_{{Cu}^{2 +} / {Cu}^{+}} = 0.15 V, {E^{°}}_{{In}^{2 +} / {In}^{+}} = - 0.4 V, {E^{°}}_{{In}^{3 +} / In} = - 0.42 V

.

HARD

12th ICSE

IMPORTANT

All In One ISC Chemistry Class 12>Chapter 3 - Electrochemistry>Chapter Practice>Q 27

A current of

3.7 A

is passed for

6 h

between nickel electrodes in

0.5 L

of a

20 M

solution of

Ni ({NO}_{3})_{2}

. What will be the molarity of solution at the end of electrolysis?

HARD

12th ICSE

IMPORTANT

All In One ISC Chemistry Class 12>Chapter 3 - Electrochemistry>Chapter Practice>Q 28

Calculate the emf for the given cell at

25^{°} C

:

Cr {Cr}^{3 +} (0.1 M) ∥ {Fe}^{2 +} (0.01 M) | Fe

[Given,

E °_{({Cr}^{3 +} Cr)} = - 0.74 V, E °_{({Fe}^{2 +} Fe)} = - 0.44 V

].