Tag: chemical reactions

Questions Related to chemical reactions

A current being passed for two hour through a solution of an acid liberating 11.2 litre of oxygen at NTP at anode. What will be the amount of copper deposited at the cathode by the same current when passed through a solution of copper sulphate for the same time?

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  1. 16 g

  2. 63 g

  3. 31.5 g

  4. 8 g

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Correct Option: B
Explanation:

Solution:- (B) $63 \; g$

At STP,
$1$ mole of oxygen gas $= 32 \; g = 22.4 \; L$
Therefore,
$11.2 \; L$ of ${O} _{2} = \cfrac{32}{22.4} \times 11.2 = 16 \; g$
Therefore,
$\cfrac{{M} _{Cu}}{{M} _{{O} _{2}}} = \cfrac{{E} _{Cu}}{{E} _{O}}$
$\Rightarrow \cfrac{{M} _{Cu}}{16} = \cfrac{\left( \cfrac{63}{2} \right)}{\left( \cfrac{16}{2} \right)}$
$\Rightarrow {M} _{Cu} = 63 \; g$
Hence the amount of copper deposited at the cathode is $63 \; g$.

A current of 9.65 Ampere flowing for 10 minutes deposits 3 g of metal which is monovalent, the atomic mass of metal is a:

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  1. 10

  2. 50

  3. 30

  4. 96.5

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Correct Option: B
Explanation:

Solution:- (B) $50$

Weight of metal deposited $= 3 \; g$
Quantity of electricity passed $\left( q \right)$-
$q = I \times t$
Given:-
$I = 9.65 A$
$t = 10 \; min = 10 \times 60 = 600 \; sec$
$\therefore q = 9.65 \times 600 = 5790 \; C$
Now, as we know that,
Eq. wt. of metal $= \cfrac{\text{Weight of metal}}{q} \times F$
$\Rightarrow$ Eq. wt. of metal $= \cfrac{3}{5790} \times 96500 = 50 \; g$
As the metal is monovalent, atomic weight of metal will be equal to its equivalent weight.
Therefore,
Atomic weight of metal $= 50 \; g$

Which of the following ($1\ M$) conducts more electricity?

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  1. Sulphuric acid

  2. Boric acid

  3. Nitric acid

  4. Phosphorous acid

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Correct Option: A

In metallic conductor the current is conducted by flow of:

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  1. ions

  2. atoms

  3. electrons

  4. molecules

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Correct Option: C
Explanation:

In metallic conductor the current is conducted by flow of free electrons.Ions contain the free electron therefore they conducts the electricity.

The charge required to deposit 40.5 g of Al(atomic mass=27.0 g) from the fused ${ Al } _{ 2 }{ \left( { SO } _{ 4 } \right) } _{ 3 }$ is :

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  1. $4.34\times { 10 }^{ 5 }C$

  2. $43.4\times { 10 }^{ 5 }C$

  3. $1.44\times { 10 }^{ 5 }C$

  4. None of these

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Correct Option: A

Electrolytic conductivity of $0.3 M$ solution of $KCI$ at $298 K $is $3.72$ x ${10}^{-2}Scm^{-1}$.Calculate its molar conductivity ($S cm^{2} mol ^{-1}$) 

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  1. $124$

  2. $30.56$

  3. $192$

  4. $185$

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Correct Option: A
Explanation:

Given,

$k=3.72\times 10^{-2}\ Scm^{-1}$
$c=0.3M$

Molar conductivity($m$) is given by,

$m=\dfrac{k\times 1000}{c}$

$\Rightarrow m=\dfrac{3.72\times 10^{-2}\times 1000}{0.3}$

$\Rightarrow m=124\ S\ cm^2mol^{-1}$

Resistance of decimolar solution is 50 ohm. If electrodes of surface area 0.0004 $m^2$ each are placed at a distance of 0.02 m then conductivity of solution is : 

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  1. $1 \,s\,cm^{-1}$

  2. $0.01 \,s\,cm^{-1}$

  3. $0.001 \,s\,cm^{-1}$

  4. $10 \,s\,cm^{-1}$

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Correct Option: C

Which statement is not correct ?

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  1. Conductance of an electrolytic solution increase with dilution

  2. Conductance of an electrolytic solution decrease with dilution

  3. specific conductance of an electrolytic solution decrease with dilution

  4. Equivalent conductance of an electrolytic solution increase with dilution

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Correct Option: C

Pure water consists almost entirely of:

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  1. molecules

  2. ions

  3. atoms

  4. ions and molecules

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Correct Option: A
Explanation:

Water has very low ionisation constant so it dissociates very low and pure water is consists almost entirely of molecules.

Molten potassium chloride conducts electricity due to the presence of  _______ .

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  1. free electron

  2. free ions

  3. free molecules

  4. atom of potassium & chloride

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Correct Option: B