Electrochemistry MCQ Questions & Answers in Physical Chemistry | Chemistry

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211. Electrode potential of the half cell $$Pt\left( s \right)\left| {Hg\left( l \right)} \right|H{g_2}C{l_2}\left( s \right)\left| {C{l^ - }\left( {aq} \right)} \right.$$       can be increased by :

A Increasing $$\left[ {C{l^ - }} \right]$$
B Decreasing $$\left[ {C{l^ - }} \right]$$
C Increasing $$H{g_2}C{l_2}\left( s \right)$$
D Decreasing $$Hg\left( l \right)$$
Answer :   Decreasing $$\left[ {C{l^ - }} \right]$$

212. Fill in the blanks with appropriate words.
The electrolytic solution is always neutral because the total charge on $$\underline {\left( {\text{i}} \right)} $$  is equal to $$\underline {\left( {{\text{ii}}} \right)} $$  on $$\underline {\left( {{\text{iii}}} \right)} .$$  Unlike the metallic conductor, the electrolyte conducts the electric current by virtue of movement of its $$\underline {\left( {{\text{iv}}} \right)} .$$  The property due to which a metal tends to go into solution in term of positive ions is known as $$\underline {\left( {\text{v}} \right)} .$$
(i), (ii), (iii), (iv) and (v) respectively are

A cations, partial charge, anions, electrons, reduction
B cations, total charge, anions, ions, oxidation
C cations, ionic charge, anions, atoms, dissolution
D cations, partial charge, anions, molecules, electrolysis.
Answer :   cations, total charge, anions, ions, oxidation

213. The specific conductance of a $$0.1$$ $$N$$ $$KCl$$  solution at $${23^ \circ }C$$  is $$0.012\,{\Omega ^{ - 1}}\,c{m^{ - 1}}.$$   The resistance of cell containing the solution at the same temperature was found to be $$55\,\Omega .$$  The cell constant will be

A $$0.142\,c{m^{ - 1}}$$
B $$0.66\,c{m^{ - 1}}$$
C $$0.918\,c{m^{ - 1}}$$
D $$1.12\,c{m^{ - 1}}$$
Answer :   $$0.66\,c{m^{ - 1}}$$

214. What will be standard cell potential of galvanic cell with the following reaction?
$$2C{r_{\left( s \right)}} + 3Cd_{\left( {aq} \right)}^{2 + } \to 2Cr_{\left( {aq} \right)}^{3 + } + 3C{d_{\left( s \right)}}$$
$$\left[ {{\text{Given:}}\,E_{\frac{{C{r^{3 + }}}}{{Cr}}}^ \circ = - 0.74\,V\,\,{\text{and}}\,\,E_{\frac{{C{d^{2 + }}}}{{Cd}}}^ \circ = - 0.40\,V} \right]$$

A 0.74 $$V$$
B 1.14 $$V$$
C 0.34 $$V$$
D - 0.34 $$V$$
Answer :   0.34 $$V$$

215. Match the column I with column II and mark the appropriate choice.
Column I Column II
a. $$P{b_{\left( s \right)}} + SO_{4\left( {aq} \right)}^{2 - } \to PbS{O_{4\left( s \right)}} + 2{e^ - }$$ 1. Rusting of iron
b. $$2SO_{4\left( {aq} \right)}^{2 - } \to {S_2} O_{8\left( {aq} \right)}^{2 - } + 2{e^ - }$$ 2. Reaction at anode in lead storage battery
c. $$2{H_{2\left( g \right)}} + 4OH_{\left( {aq} \right)}^ - \to 4{H_2}{O_{\left( l \right)}} + 4{e^ - }$$ 3. Electrolysis of concentrated $${H_2}S{O_4}$ $
d. $$2F{e_{\left( s \right)}} + {O_{2\left( g \right)}} + 4H_{\left( {aq} \right)}^ + \to 2Fe_ {\left( {aq} \right)}^{2 + } + 2{H_2}{O_{\left( l \right)}}$$ 4. Reaction at anode in fuel cell

A a - 1, b - 2, c - 3, d - 4
B a - 2, b - 3, c - 4, d - 1
C a - 3, b - 4, c - 1, d - 2
D a - 4, b - 1, c - 2, d - 3
Answer :   a - 2, b - 3, c - 4, d - 1

216. Given,
$$\left( {\text{i}} \right)C{u^{2 + }} + 2{e^ - } \to Cu,$$     $${E^ \circ } = 0.337\,V$$
$$\left( {{\text{ii}}} \right)C{u^{2 + }} + {e^ - } \to C{u^ + },$$     $${E^ \circ } = 0.153\,V$$
Electrode potential, $${E^ \circ }$$ for the reaction,
$$C{u^ + } + {e^ - } \to Cu,$$    will be

A 0.52$$\;V$$
B 0.90$$\,V$$
C 0.30$$\,V$$
D 0.38$$\,V$$
Answer :   0.52$$\;V$$

217. The standard reduction potentials of $$C{u^{2 + }}\left| {Cu\,{\text{and}}\,C{u^{2 + }}} \right|C{u^ + }$$     are $$0.337 V$$  and $$0.153$$  respectively. The standard electrode potential of $$C{u^ + }\left| {Cu\,} \right.$$  half cell is

A $$0.184 V$$
B $$0.827 V$$
C $$0.521 V$$
D $$0.490 V$$
Answer :   $$0.521 V$$

218. For the electrochemical cell
$$Pt\left( s \right)\mathop {\left| {{H_2}\left( g \right)} \right|}\limits_{1\,atm} {H^ + }\left( {1\,M} \right)\left| {,Cu\left( s \right)} \right.$$       which one of the following statements is true ?

A $${H^ + }\,ions$$   are formed at anode and $$Cu$$  is deposited at cathode.
B $${H_2}$$  is liberated at cathode and $$Cu$$  is deposited at anode.
C Oxidation occurs at cathode.
D Reduction occurs at anode.
Answer :   $${H^ + }\,ions$$   are formed at anode and $$Cu$$  is deposited at cathode.

219. The standard electrode potentials $$\left( {E_{{M^ + }/M}^ \circ } \right)$$   of four metals $$A, B, C$$   and $$D$$ are $$ - 1.2\,V,0.6\,V,0.85\,V$$    and $$ - 0.76\,V,$$  respectively. The sequence of deposition of metals on applying potential is :

A $$A,C,B,D$$
B $$B,D,C,A$$
C $$C,B,D,A$$
D $$D,A,B,C$$
Answer :   $$C,B,D,A$$

220. The specific conductivity of $$\frac{N}{{10}}KCl$$   solution at $${20^ \circ }C$$  is $$0.0212\,oh{m^{ - 1}}c{m^{ - 1}}$$    and the resistance of the cell containing this solution at $${20^ \circ }C$$  is $$55\,ohm.$$  The cell constant is

A $$3.324\,c{m^{ - 1}}$$
B $$1.166\,c{m^{ - 1}}$$
C $$2.372\,c{m^{ - 1}}$$
D $$3.682\,c{m^{ - 1}}$$
Answer :   $$1.166\,c{m^{ - 1}}$$