The reaction taking place in an electrochemical cell under standard conditions is Fe 2 + aq + Ag + aq ⇌ Fe 3 + aq + Ag s . Write two half-equations for this reaction. For each, state whether oxidation or reduction is occurring.

Consider the given cell reaction, Fe 2 + aq + Ag + aq ⇌ Fe 3 + aq + Ag s Oxidation half-reaction: In this reaction, an electron is lost from a Fe 2 + ion. Fe 2 + aq ⇌ Fe 3 + aq + e - Reduction half-reaction: In this reaction, an electron is gained by a Ag + ion. Ag + aq + e - ⇌ Ag s

The standard electrode potential for the half-cell containing Fe 2 + aq and Fe 3 + aq is + 0 . 77 V . Use the relationship E = E ° + 0 . 059 z log oxidised form reduced form to calculate the electrode potential at 298 K if the concentration of Fe 2 + aq is 0 . 02 mol dm - 3 and the concentration of Fe 3 + aq is 0 . 1 mol dm - 3 .

Given, E ∘ Fe 3 + / Fe 2 + = + 0 . 77 V , Fe 2 + = 0 . 02 mol dm - 3 and Fe 3 + = 0 . 1 mol dm - 3 . E = E ° + 0 . 059 z log oxidised form reduced form = 0 . 77 + 0 . 059 1 log 0 . 1 0 . 02 = 0 . 811 V Therefore, E = 0 . 811 V .

The standard electrode potential for the half-cell containing Ag + aq and Ag s is + 0 . 80 V . Calculate the electrode potential at 298 K if the concentration of Ag + aq is 0 . 05 mol dm - 3 .

Given, E ∘ Ag + / Ag = + 0 . 80 V , Ag + aq = 0 . 05 mol dm - 3 , and = 298 K . We know that, E = E ° + 0 . 059 z log oxidised form reduced form = 0 . 80 + 0 . 059 1 log 0 . 05 = 0 . 723 V Therefore, E = 0 . 723 V .

EASY

AS and A Level

IMPORTANT

Earn 100

An aqueous solution of silver nitrate is electrolysed. Explain why silver nitrate becomes acidic during this electrolysis?

Important Questions on Electrochemistry

MEDIUM

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 20 - Electrochemistry>EXAM-STYLE QUESTIONS>Q 8

Calculate the mass of silver deposited at the cathode when the electrolysis is carried out for exactly

35 \min

using a current of

0.18 A

. (

A_{r} [Ag] = 108; F = 96500 C

EASY

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 20 - Electrochemistry>EXAM-STYLE QUESTIONS>Q 9

The reaction taking place in an electrochemical cell under standard conditions is

{Fe}^{2 +} (aq) + {Ag}^{+} (aq) \overset{}{⇌} {Fe}^{3 +} (aq) + Ag (s)

. Write two half-equations for this reaction. For each, state whether oxidation or reduction is occurring.

EASY

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 20 - Electrochemistry>EXAM-STYLE QUESTIONS>Q 9

The standard electrode potential for the half-cell containing

{Fe}^{2 +} (aq)

and

{Fe}^{3 +} (aq)

+ 0.77 V

. Use the relationship

E = E^{°} + \frac{0.059}{z} \log \frac{[oxidised form]}{[reduced form]}

to calculate the electrode potential at

298 K

if the concentration of

{Fe}^{2 +} (aq)

0.02 mol {dm}^{- 3}

and the concentration of

{Fe}^{3 +} (aq)

0.1 mol {dm}^{- 3}

EASY

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 20 - Electrochemistry>EXAM-STYLE QUESTIONS>Q 9

The standard electrode potential for the half-cell containing

{Fe}^{2 +} (aq)

and

{Fe}^{3 +} (aq)

+ 0.77 V

. Using the relationship

E = E^{°} + \frac{0.059}{z} \log \frac{[oxidised form]}{[reduced form]}

explain why the standard electrode potential for the half-cell containing

{Fe}^{2 +} (aq)

and

{Fe}^{3 +} (aq)

is always

+ 0.77 V

if there are equimolar concentrations of

{Fe}^{2 +} (aq)

and

{Fe}^{3 +} (aq)

EASY

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 20 - Electrochemistry>EXAM-STYLE QUESTIONS>Q 9

The standard electrode potential for the half-cell containing

{Ag}^{+} (aq)

and

Ag (s)

+ 0.80 V

. Calculate the electrode potential at

298 K

if the concentration of

{Ag}^{+} (aq)

0.05 mol {dm}^{- 3}

EASY

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 20 - Electrochemistry>EXAM-STYLE QUESTIONS>Q 9

Predict whether the reaction ${Fe}^{2 +} (aq) + {Ag}^{+} (aq) \overset{}{⇌} {Fe}^{3 +} (aq) + Ag (s)$ is likely to occur at the concentrations ${Fe}^{2 +} (aq) 0.05 mol {dm}^{- 3}$ , ${Fe}^{3 +} (aq) 0.1 mol {dm}^{- 3}$ and ${Ag}^{+} (aq) 0.05 mol {dm}^{- 3}$ . Explain your answer.

Given, ${E^{\circ}}_{{Ag}^{+} / Ag} = + 0.80 V$ and ${E^{\circ}}_{{Fe}^{3 +} / {Fe}^{2 +}} = + 0.77 V$ .

EASY

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 20 - Electrochemistry>EXAM-STYLE QUESTIONS>Q 10

Concentrated aqueous sodium chloride can be electrolysed in the laboratory using graphite electrodes. Write the formulae for all the ions present in an aqueous solution of sodium chloride.

EASY

AS and A Level

IMPORTANT

Chemistry for Cambridge International AS & A Level Coursebook with Digital Access (2 Years)>Chapter 20 - Electrochemistry>EXAM-STYLE QUESTIONS>Q 10

Concentrated aqueous sodium chloride can be electrolysed in the laboratory using graphite electrodes. Write half-equations to show the reaction at the anode.

An aqueous solution of silver nitrate is electrolysed. Explain why silver nitrate becomes acidic during this electrolysis?

Important Questions on Electrochemistry

Learn and Prepare for any exam you want !