Question

Tarnished silver contains Ag₂S. Can this tarnish be removed by placing tarnished silverware in an aluminium pan containing an inert electrolytic solution such as NaCl? The standard electrode potential for half reaction : Ag₂S(s) + 2e⁻ → 2Ag(s) + S²⁻ is –0.71 V and for Al³⁺ + 3e⁻ → 2Al(s) is –1.66 V.

Define the following :

Calculate emf of the following cell at 25 °C : Zn(s)|Zn²⁺(0.1M) || Cd²⁺(0.01M) | Cd(s) Given : E°(Cd²⁺/Cd) = –0.40 V E°(Zn²⁺/Zn) = –0.76 V [log 10 = 1]

Calculate emf of the following cell at 25°C : Zn (s) | Zn²⁺ (0·001M) || Cd²⁺ (0·1 M) | Cd (s) Given : E°(Zn²⁺/Zn) = – 0·76 V, E°(Cd²⁺/Cd) = – 0·40 V [log 10 = 1]