Consider the cell Pt ( s ) H 2 ( s ) ( latm ) H + aq , H + = 1 | | Fe 3 + ( aq ) , Fe 2 + ( aq ) ∣ Pt ( s ) Given: E Fe 3 + / Fe 2 + ° = 0 . 771 V and E H + / 1 2 H 2 ° = 0 V , T = 298 K If the potential of the cell is 0 . 712 V the ratio of concentration of Fe 2 + to Fe 3 + is (Nearest integer)

Step-by-step solution

Cell reaction which occurs: 1 2 H 2 (   g ) + Fe 3 +  (aq.)  ⟶ H + ( aq ) + Fe 2 +  (aq.)  Using Nernst' equation: E = E o - 0 . 059 1 log Fe 2 + Fe 3 + ⇒ 0 . 712 = ( 0 . 771 - 0 ) - 0 . 059 1 log Fe 2 + Fe 3 + ⇒ log Fe 2 + Fe 3 + = ( 0 . 771 - 0712 ) 0 . 059 = 1 ⇒ Fe 2 + Fe 3 + = 10