NTA Abhyas NEET2020ChemistryElectrochemistryPractice
If the half-cell reactions are given as (i) Fe 2 + + 2 e − → Fe s ; E o = − 0.44 V (ii) 2 H + ( a q ) + O 2 ( g ) + 2 e → H 2 O ( l ) ; E o = + 1.23 V The E o for the reaction F e s + 2 H + + O 2 g → F e 2 + ( a q ) + H 2 O l
Options
- A– 0.79 V
- B– 1.67 V
- C1.67 V
- D0.79 V
Correct answer
C. 1.67 V
Step-by-step solution
Subtracting equation (i) from (ii) we get equation (iii) as follows F e ( s ) + 2 H + + 1 2 O 2 → F e 2 + ( a q ) + H 2 O ( l ) …(iii) So, E o = E o 2 - E o 1 = + 1.23 - ( - 0.44 ) = + 1.67 V .