Electrochemistry Test

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Electrochemistry Test - 73

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Weekly Quiz Competition

Question 1
1 / -0

According to the first law of Faraday the weight of a substance discharge at the electrode is

A
$$W=ZQ$$

B
$$W=eF$$

C
$$W=\dfrac{Z}{F}It$$

D
$$W=ZI$$

Solution

Faraday further observed that 1 Faraday (96,485C) of charge liberates 1 gram equivalent of the substance at the electrodes. This means that 1 C will liberate one gram equivalent of a $$\dfrac{substance}{96,485}$$, which is the electrochemical equivalent (Z) of the substance
Question 2
1 / -0

Which of the following represents the first law of Faraday

A
$$E=mc^{2}$$

B
$$E=hv$$

C
$$m=ect$$

D
$$PV=nRT$$

Solution

The mass of the substance (m) deposited or liberated at any electrode is directly proportional to the quantity of electricity or charge (Q) passed.
Question 3
1 / -0

In an electrochemical cell___________

A
potential energy changes into kinetic energy

B
kinetic energy changes into potential energy

C
chemical energy changes into electrical energy

D
electrical energy changes into chemical energy

Solution

In a galvanic cell (electrochemical cell), the spontaneous chemical reaction generates electric current.

Option C is correct.
Question 4
1 / -0

Faraday has the dimensions of

A
Coulombs

B
Coulombs equivalent

C
Coulombs per equivalent

D
Coulombs per degree Kelvin

Solution

Coulomb is the SI unit of electric charge. Therefore, the dimensional formula of Coulomb is the same as that of the electric charge. Therefore, Coulomb is dimensionally represented as $$[M^0 L^0 T^1 I^1]$$.
Question 5
1 / -0

The value of one Faraday is

A
$$95500\ C\ mol^{-1}$$

B
$$96550\ C\ mol^{-1}$$

C
$$96500\ C\ mol^{-1}$$

D
$$98500\ C\ mol^{-1}$$

Solution

Faraday's Constant is given the symbol $$F$$ and is defined as the charge in coulumbs (C) of 1 mole of electrons. Faraday's constant is approximately 96485 $$C mol^{-1}$$. We can calculate (F) by multiplying the charge on one electron $$(1.602 * 10^-19)$$ by Avogadro's number $$(6.022*10^23)$$.
therefore the Answer is $$96500\ Cm^{-1}$$
Question 6
1 / -0

Faraday constant

A
Is a numerical constant

B
Depends on equivalent

C
Depends upon the current passed

D
Depends on the number of electrons

Solution

The charge of 1 mole of electrons is called the Faraday constant, F.
It is calculated by multiplying the charge of one electron by the Avogadro constant. i.e,
$$F=eN_A =(1.6×10^{−19})(6.023×10^{23})=9.648×10^4C.mol^{−1}$$
.It is a universal constant.
Question 7
1 / -0

Which of the following statement is true for a electrochemical cell?

A
$$H_2$$ is cathode and $$Cu$$ is anode

B
$$H_2$$ is anode and $$Cu$$ is cathode

C
Reduction occurs at $$H_2$$ electrode

D
Oxidation occurs at $$Cu$$ electrode

Solution

In electrochemical cell, $$H_2$$ is anode and $$Cu$$ is cathode because of their standard reduction potential value.
Question 8
1 / -0

Which of the following statements about galvanic cell is incorrect?

A
Anode is positive

B
Oxidation occurs at the electrode with lower reduction potential

C
Cathode is positive

D
Reduction occurs at cathode

Solution

Anode has negative polarity in galvanic cell.

Option A is correct.
Question 9
1 / -0

Lead pipes are corroded quickly by

A
Dil. $$H_{2}SO_{4}$$

B
Conc. $$H_{2}SO_{4}$$

C
Acetic acid

D
Water

Solution

Organic acids dissolve lead in the presence of oxygen. So, lead pipes are corroded quickly by acetic acid.

$$Pb+2CH_{3}COOH+\dfrac{1}{2}O_{2}\rightarrow Pb(CH_{3}COO)_{2}+H_{2}O$$
Question 10
1 / -0

For the feasibility of a redox reaction in a cell, the emf should be

A
Positive

B
Fixed

C
Zero

D
Negative

Solution

Answer A
Solution :
Any redox reaction would occur spontaneously if the free energy charnge $$(ΔG)$$ is negative.
$$ΔG^∘=nFE^2$$
Where n is the number of electrons involved, F is the value of faraday and $$E^∘$$ is the cell emf. $$ΔG^2$$ can be negative if $$2$$ is $$\textbf{positive.}$$

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Electrochemistry Test - 73

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Electrochemistry Test - 73

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Question 1

$$W=ZQ$$

$$W=eF$$

$$W=\dfrac{Z}{F}It$$

$$W=ZI$$

Solution

Question 2

$$E=mc^{2}$$

$$E=hv$$

$$m=ect$$

$$PV=nRT$$

Solution

Question 3

potential energy changes into kinetic energy

kinetic energy changes into potential energy

chemical energy changes into electrical energy

electrical energy changes into chemical energy

Solution

Question 4

Coulombs

Coulombs equivalent

Coulombs per equivalent

Coulombs per degree Kelvin

Solution

Question 5

$$95500\ C\ mol^{-1}$$

$$96550\ C\ mol^{-1}$$

$$96500\ C\ mol^{-1}$$

$$98500\ C\ mol^{-1}$$

Solution

Question 6

Is a numerical constant

Depends on equivalent

Depends upon the current passed

Depends on the number of electrons

Solution

Question 7

$$H_2$$ is cathode and $$Cu$$ is anode

$$H_2$$ is anode and $$Cu$$ is cathode

Reduction occurs at $$H_2$$ electrode

Oxidation occurs at $$Cu$$ electrode

Solution

Question 8

Anode is positive

Oxidation occurs at the electrode with lower reduction potential

Cathode is positive

Reduction occurs at cathode

Solution

Question 9

Dil. $$H_{2}SO_{4}$$

Conc. $$H_{2}SO_{4}$$

Acetic acid

Water

Solution

Question 10

Positive

Fixed

Zero

Negative

Solution

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