Electrochemistry · Question 15

Consider the following electrochemical cell at 298 K Pt | HSnO2-(aq) | Sn(OH)62-(aq) | OH-(aq) | Bi2O3(s) | Bi(s). If the reaction quotient at a given time is 106, then the cell EMF ( Ecell) is 10-1 V (Nearest integer). Given the standard half-cell reduction potential as E Bi2O3/Bi,OH- = -0.44 V and E Sn(OH)62-/HSnO2-,OH- = -0.90 V

Consider the following reduction processes : Al3+ + 3e- Al(s), E0 = -1.66 V Fe3+ + e- Fe2+, E0 = +0.77 V Co3+ + e- Co2+, E0 = +1.81 V Cr3+ + 3e- Cr(s), E0 = -0.74 V The tendency to act as reducing agent decreases in the order :

1. Al > Fe2+ > Cr > Co2+
2. Al > Cr > Co2+ > Fe2+
3. Cr > Fe2+ > Al > Co2+
4. Al > Cr > Fe2+ > Co2+

Consider the following electrochemical cell : Pt | O2(g)(1 bar) | HCl(aq) || M2+(aq, 1.0 M) | M(s) The pH above which, oxygen gas would start to evolve at anode is (nearest integer). [Given : . arrayl E M2+/M = 0.994 V \ E O2/H2O = 1.23 V array \ standard reduction potential and RTF(2.303) = 0.059 V at the given condition]

The pH and conductance of a weak acid (HX) were found to be 5 and 4 10-5 S, respectively. The conductance was measured under standard condition using a cell where the electrode plates having a surface area of 1 cm2 were at a distance of 15 cm apart. The value of the limiting molar conductivity is S m2 mol-1. (nearest integer) (Given : degree of dissociation of the weak acid ( ) 1)

For a closed circuit Daniell cell, which of the following plots is the accurate one at a given temperature?

1. [figure]
2. [figure]
3. [figure]
4. [figure]

MX is a sparingly soluble salt that follows the given solubility equilibrium at 298 K. MX(s) M+(aq) + X-(aq); Ksp = 10-10 If the standard reduction potential for M+(aq) + e- M(s) is ( E M+/M ) = 0.79 V, then the value of the standard reduction potential for the metal/metal insoluble salt electrode E X-/MX(s)/M is mV. (nearest integer) [Given: 2.303RTF = 0.059 V]

Consider the following half cell reaction Cr2O72-(aq) + 6e- + 14H+(aq) 2Cr3+(aq) + 7H2O( ) The reaction was conducted with the ratio of [ Cr3+]2[ Cr2O72-] = 10-6. The pH value at which the EMF of the half cell will become zero is . (nearest integer value) [Given: standard half cell reduction potential E Cr2O72-,H+/Cr3+ = 1.33 V, 2.303RTF = 0.059 V.]

Given below are two statements : In the light of the given statements, choose the correct answer from the options given below :

1. Both Statement I and Statement II are true
2. Statement I is true but Statement II is false
3. Both Statement I and Statement II are false
4. Statement I is false but Statement II is true

1 Faraday of electricity was passed through Cu2+(1.5 M, 1 L)/Cu and 0.1 Faraday was passed through Ag+(0.2 M, 1 L)/Ag electrolytic cells. After this the two cells were connected as shown below to make an electrochemical cell. The emf of the cell thus formed at 298 K is mV (nearest integer) [figure] Given : E Cu2+/Cu = 0.34 V E Ag+/Ag = 0.8 V 2.303RTF = 0.06 V

Given below are two statements : 1 M aqueous solutions of each of Cu(NO3)2, AgNO3, Hg2(NO3)2, Mg(NO3)2 are electrolysed using inert electrodes. Given: E0Ag+/Ag = 0.80 V, E0Hg22+/Hg = 0.79 V, E0Cu2+/Cu = 0.34 V and E0Mg2+/Mg = -2.37 V. In the light of the above statements, choose the most appropriate answer from the options given below :

1. Both Statement I and Statement II are incorrect
2. Statement I is incorrect but Statement II is correct
3. Statement I is correct but Statement II is incorrect
4. Both Statement I and Statement II are correct