Consider the following relations for emf of an electrochemical cell:
| (a) | emf of a cell = (Oxidation potential of the anode) – (Reduction potential of the cathode) |
| (b) | emf of a cell = (Oxidation potential of the anode) + (Reduction potential of the cathode) |
| (c) | emf of a cell = (Reduction potential of the anode) + (Reduction potential of the cathode) |
| (d) | emf of a cell = (Oxidation potential of the anode) – (Oxidation potential of the cathode) |
Which of the following combinations correctly represents the relation for the emf of the cell?
| 1. | (a) and (b) | 2. | (c) and (d) |
| 3. | (b) and (d) | 4. | (c) and (a) |
Molar conductivities at infinite dilution of
NaCl, HCl, and are 126.4, 425.9, and 91.0 S cm2 mol–1 respectively.
for will be:
| 1. | \(180.5~S~cm^2~mol^{-1}\) | 2. | \(290.8~S~cm^2~mol^{-1}\) |
| 3. | \(390.5~S~cm^2~mol^{-1}\) | 4. | \(425.5~S~cm^2~mol^{-1}\) |
Given the standard electrode potentials:
| K+/K = –2.93 V |
| Ag+/Ag = 0.80 V |
| Hg2+/Hg = 0.79 V |
| Mg2+/Mg = –2.37 V |
| Cr3+/Cr = – 0.74 V |
| 1. | Cr < Mg < K < Ag < Hg | 2. | Mg < K < Ag < Hg < Cr |
| 3. | K < Ag < Hg < Cr < Mg | 4. | Ag < Hg < Cr < Mg < K |
The correct statement about the given galvanic cell equation is:
Zn(s) + 2Ag+(aq) → Zn2+(aq) + 2Ag(s)
| 1. | The current will flow from silver to zinc in the external circuit. |
| 2. | The current will flow from zinc to silver in the external circuit. |
| 3. | The current will flow from silver to zinc in the internal circuit. |
| 4. | The current will flow from zinc to silver in the internal circuit. |
2Cr(s) + 3Cd2+(aq) → 2Cr3+(aq) + 3Cd
;
The value of in the above reaction will be-
| 1. | -196.83 kJ
|
2. | 196.83 kJ
|
| 3. | 186.83 kJ
|
4. | -186.83 kJ |
The incorrect statement(s) among the following is/are:
| (a) | The unit of conductivity is S cm–2. |
| (b) | Specific Conductivity of weak and strong electrolytes always decreases with a decrease in concentration. |
| (c) | The unit of molar conductivity is S cm2 mol–1. |
| (d) | Molar conductivity increases with an increase in concentration. |
1. Only (a)
2. (a) and (d)
3. (b) and (d)
4. (a) and (c)
The conductivity of 0.20 M solution of KCl at 298 K is 0.0248 S cm–1. The molar conductivity will be -
| 1. | 124 S cm2 mol-1 | 2. | 134 S cm2 mol-1 |
| 3. | 128 S cm2 mol-1 | 4. | 136 S cm2 mol-1 |
The electricity required in coulombs for the oxidation of 1 mole of FeO to \(Fe_{2} O_{3 }\) is:
| 1. | 964.87 C | 2. | 96487 C |
| 3. | 96.487 C | 4. | 9.6487 C |
\(Fe^{2+}(aq) \ + \ Ag^{+}(aq) \ \rightarrow \ Fe^{3+}(aq) \ + \ Ag(s)\)
\(E_{Fe^{3+}/Fe^{2+}}^{o} \ = \ 0.77 \ V; \ E_{Ag^{+}/Ag}^{o} \ = \ 0.80 \ V\)
The value of \(\Delta G_{r}^{o} \) in the above reaction will be:
1. +
2.
3.
4. -186.83 J
The value of Ecell in the reaction below will be:
\(\small{Pt(s)|Br^{-}(0.010 \ M)|Br_{2}(l) \ ||H^{+}(0.030 \ M)|H_{2}(g)(1 \ bar)|Pt(s)}\)
\(E_{Br^{-}/Br_{2}}^{o} \ = \ -1.09 \ V\)
1. +1.298 V
2. –1.398 V
3. –1.298 V
4. –1.198 V