JEE Main 2026 Chemistry question
One half cell in a voltaic cell is constructed by dipping silver rod in AgNO₃ solution of unknown concentration, other half cell is Zn rod dipped in 1 molar solution of ZnSO₄. A voltage of 1.60 V is measured at 298 K for this cell. What is the concentration of Ag⁺ ions used in terms of log x (x=[Ag⁺])? Given: E°(Zn²⁺/Zn)=−0.76V, E°(Ag⁺/Ag)=+0.80V, 2.303RT/F=0.059V
Answer: (B)
Solution
E°cell=0.80−(−0.76)=1.56V. Nernst: 1.60=1.56−(0.059/2)log(1/x²)=1.56+0.059logx, giving logx=0.04/0.059=4/5.9.