For hydrogen-oxygen fuel cell, the cell reaction is: 2 H 2( g )+ O 2( g ) arrow 2 H 2 O ( l ) If Δ G f o ( H 2 O )=-237.2 kJ mol -1, then emf of this cell is:

Question

For hydrogen-oxygen fuel cell, the cell reaction is: 2 H 2( g )+ O 2( g ) arrow 2 H 2 O ( l ) If Δ G f o ( H 2 O )=-237.2 kJ mol -1, then emf of this cell is: (A) + 2.46 V (B) - 2.46 V (C) + 1.23 V (D) - 1.23 V

Tardigrade Admin · Accepted Answer

Gibbs free energy, Δ G °=- nFE ° ∴ E °=(Δ G °/ nF ) =(237.2 × 1000 J /2 × 96500) =1.23 V [∵ n =2]

Q. For hydrogen-oxygen fuel cell, the cell reaction is:
$2 H_{2} (g) + O_{2} (g) \to 2 H_{2} O (l)$
If $Δ G_{f}^{o} (H_{2} O) = - 237.2 k J m o l^{- 1}$ , then emf of this cell is:

+ 2.46 V

- 2.46 V

+ 1.23 V

- 1.23 V

Gibbs free energy, $Δ G^{\circ} = - n F E^{\circ}$
$∴ E^{\circ} = \frac{Δ G ^{\circ}}{n F}$
$= \frac{237.2 \times 1000 J}{2 \times 96500}$
$= 1.23 V [∵ n = 2]$

Q. For hydrogen-oxygen fuel cell, the cell reaction is: 2H2​(g)+O2​(g)→2H2​O(l) If ΔGfo​(H2​O)=−237.2kJmol−1, then emf of this cell is: