The standard Emf of a galvanic cell involving cell reaction with n = 2 is found to be 0.295 V at 25 ºC. The equilibrium constant of the reaction would be:
(Given F = 96500 C mol–1; R = 8.314 J K–1 mol–1)
1. 4.0 × 1012
2. 1.0 × 102
3. 1.0 × 1010
4. 2.0 × 1011
In the silver plating of copper, K[Ag(CN)2] is used instead of AgNO3. The reason is:
1. | A thin layer of Ag is formed on Cu |
2. | More voltage is required |
3. | Ag+ ions are completely removed from the solution |
4. | Less availability of Ag+ ions, as Cu can not displace Ag from [Ag(CN)2]– ion |
Consider the following reaction:
\(\frac{4}{3} \mathrm{Al}(\mathrm{s})+\mathrm{O}_2(\mathrm{~g}) \rightarrow \frac{2}{3} \mathrm{Al}_2 \mathrm{O}_3(\mathrm{~s})\)
The minimum e.m.f. required to carry out the electrolysis of Al2O3 is:
(F = 96500 C mol–1)
1. 2.14 V
2. 4.28 V
3. 6.42 V
4. 8.56 V
The EMF of a Daniel cell at 298 K is E1 Zn|ZnSO4(0.01 M) || CuSO4(1.0 M)|Cu.
When the concentration of ZnSO4 is 1.0 M and that of CuSO4 is 0.01 M, the EMF is changed to E2. The correct relationship between E1 and E2 is:
1. | E1 > E2 | 2. | E1 < E2 |
3. | E1 = E2 | 4. | E2 = 0 ≠ E1 |
The following metals should be arranged so that they push one another out of the salt solution in that order:
Al, Cu, Fe, Mg, and Zn.
1. Cu <Fe<Zn< Al< Mg
2. Zn< Fe< Cu< Mg< Al
3. Mg<Cu <Zn <Fe< Al
4. Al<Zn<Fe< Cu< Mg
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 below 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 |