Electrochemistry Test

Electrochemistry

This is electrochemistry Test-02 for CBSE class 12 Chemistry.. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

According to Faraday’s Second Law of Electrolysis the amounts of different substances liberated by the same quantity of electricity passing through the electrolytic solution are proportional

A
to their atomic weight .
B
to their Atomic number
C
to their nuclear masses
D
their chemical equivalent weights
Correct

Charge on one mole of electrons - Faraday is approximately

A
98500 C $mol^–1$
B
97500 C $mol^–1$
C
96500 C $mol^–1$
Correct
D
99500 C $mol^–1$

In the primary batteries

A
the reaction occurs only once and after use over a period of time battery becomes dead and cannot be reused again
Correct
B
None of these
C
the reaction is reversed periodically and after use over a period of time and so can be reused again
D
the reaction occurs only once and after use over a period of time battery becomes dead and can be reused again

A secondary cell after use ________ recharged by passing current through it in the ________ so that it can/can’t be used again.

A
cannot be, opposite direction
B
none of these
C
can be, same direction
D
can be, opposite direction
Correct

Fuel cells are ________ that are designed to convert the energy of combustion of fuels like hydrogen, methane, methanol, etc. directly into_________.

A
Galvanic cells , hydraulic energy
B
Galvanic cells , electrical energy
Correct
C
Galvanic cells , thermal energy
D
Electrolytic cells , electrical energy

In corrosion a metal is ______ of electrons to oxygen and formation of oxides

A
None of these
B
oxidized by gain
C
oxidized by loss
Correct
D
reduced by loss

One of the simplest methods of preventing corrosion is to prevent the surface of the metallic object to come in contact with atmosphere. This can be done

A
by covering the surface with oil
B
by covering the surface with salt
C
by covering the surface with paint or by some chemicals
Correct
D
by covering the surface with citric acid

An electrochemical method is to provide a sacrificial electrode of another metal (like Mg, Zn, etc.) which corrodes itself but saves the object. A typical example is

A
Black oxidised iron
B
galvanized iron
Correct
C
painted iron
D
grounded iron

Correct arrangement of Al, Cu, Fe, Mg and Zn in the order in which they displace each other from the solution of their salts is

A
Mg, Al,Cu,Fe,Zn
B
Cu, Al,Zn,Fe, Mg
C
Mg, Al,Zn,Fe,Cu
Correct
D
Mg, Al,Zn, Cu, Fe

Calculate the standard cell potentials of galvanic cell, $∆_r G^o$and equilibrium constant of the reactions if the reaction is

A
0.36V, – 199.86 kJ $mol^–1$, K = 3.16 × $10^34$
B
0.24V, – 198.86 kJ $mol^–1$, K = 3.16 × $10^34$
C
0.34V, – 196.86 kJ $mol^–1$, K = 3.16 × $10^34$
Correct
D
0.30V, – 197.86 kJ $mol^–1$, K = 3.16 × $10^34$

Calculate the standard cell potentials of galvanic cell, ∆_r G^oand equilibrium constant of the reactions if the reaction is

A
0.03V, – 2.895 kJ $mol^–1$, 3.2
Correct
B
0.04V, – 2.955 kJ $mol^–1$, 3.2
C
0.02V, – 2.850 kJ $mol^–1$, 3.2
D
0.01V, – 2.800 kJ $mol^–1$, 3.2

Emf of the cell at 298 K is

A
2.50 V
B
2.68 V
Correct
C
2.38 V
D
2.60 V

Emf of the cell at 298 K is

A
0.48 V
B
0.50 V
C
0.53 V
Correct
D
0.55 V

Emf of the cell at 298 K is

A
0.08 V
Correct
B
0.18 V
C
0.06 V
D
0.10 V

In the button cells widely used in watches and other devices the following reaction takes place: Determine E^ofor the reaction.

A
1.005 V
B
0.913 V
C
1.159 V
D
1.105 V
Correct