1
MCQ (Single Correct Answer)

AIPMT 2008

On the basis of the following Eo values, the strongest oxidizing agent is
[Fe(CN)6]4$$-$$ $$ \to $$ [Fe(CN)6]3$$-$$ + e$$-$$;  Eo = $$-$$0.35 V

Fe2+ $$ \to $$ Fe3+ + e$$-$$;  Eo = $$-$$0.77 V
A
Fe3+
B
[Fe(CN)6]3$$-$$
C
[Fe(CN)6]4$$-$$
D
Fe2+

Explanation

Substances which have higher reduction potential are stronger oxidizing agent.

[Fe(CN)6]4$$-$$ $$ \to $$ [Fe(CN)6]3$$-$$ + e$$-$$;  Eo = $$-$$0.35 V

Fe2+ $$ \to $$ Fe3+ + e$$-$$;  Eo = $$-$$0.77 V

Higher the +ve reduction potential, stronger will be the oxidising agent. Oxidising agent oxidises other compounds and gets itself reduced easily.
2
MCQ (Single Correct Answer)

AIPMT 2007

The efficiency of a fuel cell is given by
A
$$\Delta $$G/$$\Delta $$S
B
$$\Delta $$G/$$\Delta $$H
C
$$\Delta $$S/$$\Delta $$G
D
$$\Delta $$H/$$\Delta $$G

Explanation

Efficiency of a fuel cell ($$\phi $$) = $${{\Delta G} \over {\Delta H}} \times 100$$

Generally, fuel cells are expected to have an efficiency of 100 percent.
3
MCQ (Single Correct Answer)

AIPMT 2007

The equilibrium constant of the reaction:
Cu(s) + 2Ag+(aq) $$ \to $$ Cu2+(aq) + 2Ag(s);
Eo = 0.46 V at 298 K is
A
2.0 $$ \times $$ 1010
B
4.0 $$ \times $$ 1010
C
4.0 $$ \times $$ 1015
D
2.4 $$ \times $$ 1010

Explanation

RT ln K = nFE°

ln K = $${{nFE^\circ } \over {RT}}$$

= $${{2 \times 0.46} \over {0.0591}}$$

$$ \Rightarrow $$ K = 4 $$ \times $$ 1015
4
MCQ (Single Correct Answer)

AIPMT 2006

A hypothetical electrochemical cell is shown below.

$$A\left| {{A^ + }\left( {xM} \right)} \right|\left| {{B^ + }\left( {yM} \right)} \right|B$$

The emf measured is + 0.20 V. The cell reaction is
A
A + B+ $$ \to $$ A+ + B
B
A+ + B $$ \to $$ A + B+
C
A+ + e$$-$$ $$ \to $$ A;  B+ + e$$-$$ $$ \to $$ B
D
the cell reaction cannot be predicted.

Explanation

From the given expression:

At anode : A $$ \to $$ A+ + e

At cathode : B+ + e $$ \to $$ B

Overall reaction is : A + B+ $$ \to $$ A+ + B

EXAM MAP

Joint Entrance Examination

JEE Advanced JEE Main

Graduate Aptitude Test in Engineering

GATE CE GATE ECE GATE ME GATE IN GATE EE GATE CSE GATE PI

Medical

NEET

CBSE

Class 12