In a simple Galvanic cell , which is in standard state , half cell reactions with their appropriate oxidation potentials are
`{:(Pb (s) - 2e^(-) to Pb^(2+) (aq) E^(@) = +0.13 "volt") , (Ag (s) - e^(-) to Ag^(2+) (aq) E^(@) = - 0.80 "volt"):}`
Which of the following reaction takes place ?

Options

A. `Pb^(2+) (aq.) + 2 Ag (s) to 2 Ag^(+) (aq.) + Pb (s)`
B. `Pb^(2+) (aq.) + Ag(s) to Ag^(+) (aq.) + Pb (s)`
C. `Ag^(+) (aq.) + Pb(s) to Ag(s) + Pb^(2+) (aq.)`
D. `2 Ag^(+) (aq.) + Pb(s) to 2 Ag(s) + Pb^(2+) (aq.)`

Answer

D

Explanation

Check the spontaneity of each reaction by finding E.M.F. For a spontaneous reaction, EMF should be +ve .