HARD

Earn 100

A Daniel Cell is made at $25 ° C$ by connecting $Zn / {Zn}^{+ 2} (0.1 M, 1 litre)$ and $Cu / {Cu}^{+ 2} (0.9 M, 1 litre)$ electrodes. The cell is discharged when its EMF reaches 1.10 V. It is then charged (reversing the discharge process) by passing $0.6 F$ charge. Assume volume remains constant.

$[$ Given, $E °_{Zn / {Zn}^{+ 2}} = 0.76 V, E °_{Cu / {Cu}^{+ 2}} = - 0.34 V, 2.303 RT \div F = 0.06 V, \log 2 = 0.30]$
Select the correct option(s).

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Important Questions on Electrochemistry

HARD

Chemistry>Physical Chemistry>Electrochemistry>Electrolytic Cells and Electrolysis

How long (approximate) should water be electrolysed by passing through

100

amperes

current so that the oxygen released can completely burn

27.66 g

of diborane? (Atomic weight of

B = 10.8 u

)

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Electrolytic Cells and Electrolysis

A solution of

N i {(N O_{3})}_{2}

is electrolyzed between platinum electrodes using a current of

5

amperes for

20

minutes. What mass of

N i

is deposited at the cathode?

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Electrolytic Cells and Electrolysis

A current of $10.0 A$ flows for $2.00 h$ through an electrolytic cell containing a molten salt of metal $X$ . This results in the decomposition of $0.250 mol$ of metal $X$ at the cathode. The oxidation state of $X$ in the molten salt is:

$(F = 96, 500 C)$

EASY

Chemistry>Physical Chemistry>Electrochemistry>Electrolytic Cells and Electrolysis

A solution of

N i {(N O_{3})}_{2}

is electrolyzed between platinum electrode

0.1

Faraday electricity. How many mole of

N i

will be deposited at the cathode?

EASY

Chemistry>Physical Chemistry>Electrochemistry>Electrolytic Cells and Electrolysis

The number of electrons delivered at the cathode, during electrolysis by a current of

1 ampere in 60 seconds

is (charge on electron

= 1.60 \times 10^{- 19} C

)

HARD

Chemistry>Physical Chemistry>Electrochemistry>Electrolytic Cells and Electrolysis

108 g

of silver (molar mass

108 g {m o l}^{- 1}

) is deposited at cathode from

{A g N O}_{3} (a q)

solution by a certain quantity of electricity. The volume (in

L

) of oxygen gas produced at

273 K

and

1

bar pressure from water by the same quantity of electricity is

\frac{x}{10}

. Value of

' x'

to the nearest integer is _____.

EASY

Chemistry>Physical Chemistry>Electrochemistry>Electrolytic Cells and Electrolysis

The density of metal and equivalent weight of a metal are

10.5 g {cm}^{- 3}

and

100

, respectively. The time required for a current of

3 amp

to deposit a

0.005 mm

thick layer of the same metal on an area of

80 {cm}^{2}

is closest to

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Electrolytic Cells and Electrolysis

How many moles of platinum will be deposited on the cathode when

0.40 F

of electricity is passed through a

1.0 M

solution of

{Pt}^{4 +}

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Electrolytic Cells and Electrolysis

When 9.65 ampere current was passed for 1.0 hour into nitrobenzene in acidic medium, the amount of p-aminophenol produced is:

EASY

Chemistry>Physical Chemistry>Electrochemistry>Electrolytic Cells and Electrolysis

For electroplating,

1.5 amp

current is passed for

250 s

through

250 m L of 0.15 M

solution of

M S O_{4} .

Only

85 %

of the current was utilised for electrolysis. The molarity of

M S O_{4}

solution after electrolysis is closest to [Assume that the volume of the solution remain constant]

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Electrolytic Cells and Electrolysis

The weight of silver (at.wt.

= 108

) displaced by a quantity of electricity which displaces

5600 m L

O_{2}

STP

will be

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Electrolytic Cells and Electrolysis

A constant current (0.5 amp) is passed for 1 hour through (i) aqueous

A g N O_{3}

. (ii) aqueous

C u S O_{4}

and (iii) molten

A l F_{3}

, separately. The ratio of the mass of the metals deposited on the cathode is

[M_{Ag}, M_{Cu}, M_{Al}

are molar masses of the respective metals

]

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Electrolytic Cells and Electrolysis

When

0.1 m o l {M n O}_{4}^{2 -}

is oxidized the quantity of electricity required to completely

M n O_{4}^{2 -}

M n O_{4}^{-}

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Electrolytic Cells and Electrolysis

Oxidation of succinate ion produces ethylene and carbon dioxide gases. On passing

0.2

Faraday electricity through an aqueous solution of potassium succinate, what is the total volume of gases (at both cathode and anode) at STP (

1 atm

and

273 K

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Electrolytic Cells and Electrolysis

One litre solution of

{MgCl}_{2}

is electrolyzed completely by passing a current of

1 A

for

16 \min 5

sec. The original concentration of

{MgCl}_{2}

solution was (Atomic mass of

Mg = 24

)

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Electrolytic Cells and Electrolysis

Potassium chlorate is prepared by the electrolysis of

KCl

in basic solution

6 {OH}^{-} + {Cl}^{-} \to {ClO}_{3}^{-} + 3 H_{2} O + 6 e^{-}

. If only

60 %

of the current is utilized in the reaction, the time (rounded to the nearest hour) required to produce

10 g

{KClO}_{3}

using a current of

2 A

\dots \dots . .

(Given :

F = 96, 500 C

mol

; molar mass of

{KClO}_{3} = 122 g {mol}^{- 1}

)

MEDIUM

Chemistry>Physical Chemistry>Electrochemistry>Electrolytic Cells and Electrolysis

An acidic solution of dichromate is electrolysed for $8$ minutes using $2$ A current. As per the following equation

${Cr}_{2} O_{7}^{2 -} + 14 H^{+} + 6 e^{-} \to 2 {Cr}^{3 +} + 7 H_{2} O$
The amount of ${Cr}^{3 +}$ obtained was $0.104 g$ . The efficiency of the process $(in %)$ is (Take : $F = 96000 C$ , At. mass of chromium $= 52$ )

HARD

Chemistry>Physical Chemistry>Electrochemistry>Electrolytic Cells and Electrolysis

Calculate the molarity of a solution containing

5 g

N a O H

dissolved in the product of a

H_{2} - O_{2}

fuel cell operated at

1 A

current for

595.1

hours.

(Assume

1 F = 96500 C / m o l

of electrons and molecular weight of

N a O H

40 g m o l^{- 1}

)

EASY

Chemistry>Physical Chemistry>Electrochemistry>Electrolytic Cells and Electrolysis

During the electrolysis of molten sodium chloride, the time required to produce

0.10 mol

of chlorine gas using a current of

3 amperes

EASY

Chemistry>Physical Chemistry>Electrochemistry>Electrolytic Cells and Electrolysis

Two Faraday of electricity is passed through a solution of

C u S O_{4}

. The mass of copper deposited at the cathode is: (Atomic mass of Cu = 63.5 amu)

Important Questions on Electrochemistry

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