HARD
JEE Advanced
IMPORTANT
Earn 100

Relation between Gibb's Free Energy and EMF of a Cell Consider a 70% efficient hydrogen-oxygen fuel cell working under standard conditions at 1 bar and 298 K. Its cell reaction is

H2(g)+12O2(g)H2O(l)

The work derived from the cell on the consumption of 1.0×10-3 mol of H2(g) is used to compress 1.00 mol of a monoatomic ideal gas in a thermally insulated container. What is the change in the temperature (in K ) of the ideal gas?

The standard reduction potentials for the two half-cells are given below.

O2(g)+4H+(aq)+4e-2H2O(l),  E0=1.23 V,

2H+(aq)+2e-H2(g),  E0=0.00 V

Use F=96500 C mol-1,R=8.314 J mol-1K-1.

 

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Important Questions on Electrochemistry

MEDIUM
JEE Advanced
IMPORTANT
For the following electrochemical cell at 289 K,

Pt( s )| H 2 (g,1 bar) | H + (aq,1M)|| M 4+ (aq.), M 2+ (aq.)| Pt(s)

Ecell=0.092 V when M2+aq.M4+aq.=10x

Given: EM4+/M2+0=0.151 V ;2.303RTF=0.059

The value of x is -
HARD
JEE Advanced
IMPORTANT
For the electrochemical cell, Mg(s) Mg 2+ aq,1M Cu 2+ aq,1M Cu  s the standard emf of the cell is 2.70 V at 300 K. When the concentration of Mg 2+ is changed to x M, the cell potential changes to 2.67 V at 300 K. The value of x is ________.

(given, F R =11500 K V 1 , where F is the Faraday constant and R is the gas constants, ln 10 =2.30 )