In a typical fuel cell, the reactants (R) and products (P) are:
1. | R = H2(g), O2(g); P = H2O2(l) |
2. | R = H2(g), O2(g); P = H2O(l) |
3. | R = H2(g), O2(g), C l2(g); P = HClO4(aq) |
4. | R = H2(g), N2(g); P = NH3(aq) |
The Gibb's energy for the decomposition of \(\mathrm{A l_{2} O_{3}}\) at \(\mathrm{500~ ^\circ C}\) is as follows:
2/3Al2O3 → 4/3Al + O2 ; ∆rG = + 960 k J mol–1
The potential difference needed for the electrolytic reduction of aluminium oxide (Al2O3) at \(\mathrm{500~ ^\circ C}\) is at least,
1. 3.0 V
2. 2.5 V
3. 5.0 V
4. 4.5 V
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. | \(425.5~S~cm^2~mol^{-1}\) |
The correct expression that represents the equivalent conductance at infinite dilution of is:
(Given that are the equivalent conductances at infinite dilution of the respective ions)
1.
2.
3.
4.
Consider the following relations for emf of an electrochemical cell:
(a) | emf of cell = (Oxidation potential of anode) – (Reduction potential of cathode) |
(b) | emf of cell = (Oxidation potential of anode) + (Reduction potential of cathode) |
(c) | emf of cell = (Reduction potential of anode) + (Reduction potential of cathode) |
(d) | emf of cell = (Oxidation potential of anode) – (Oxidation potential of 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) |
The concentration of solution will change when it is placed in a container which is made of:
1. | Al | 2. | Cu |
3. | Ag | 4. | None |
The cell reaction of an electrochemical cell is \(Cu^{2+}(C_{1}) + Zn \to Cu + Zn^{2+}(C_{2})\).
The change in free energy will be the function of:
\(1. \ ln (C_{1}+C_{2})\)
2. \(ln (\frac{C_{2}}{C_{1}})\)
\(3. \ ln C_{2}\)
\(4. \ lnC_{1}\)
For the disproportionation of copper:
2Cu+ → C u2+ + C u is:
(Given for Cu+2/Cu is 0.34 V & Eº for Cu+2/Cu+ is 0.15 V )
1. 0.49 V
2. – 0.19 V
3. 0.38 V
4. – 0.38 V
A cell reaction become spontaneous when:
1. ∆Gº is negative
2. ∆Gº is positive
3. is positive
4. is negative
At infinite dilution, equivalent conductances of Ba+2 & Cl– ions are 127 & 76 ohm–1cm–1 eq–1 respectively. Equivalent conductance (ohm–1cm–1 eq–1) of BaCl2 at infinite dilution is:
1. 139.5
2. 101.5
3. 203
4. 279