A half cell reaction: is carried out in a half cell

CHEMISTRY · Single correct · AP · Chemistry · Thermodynamics and Electrochemistry · Thermodynamics and Electrochemistry

Problem

A half cell reaction:

\text{Ag}_2\text{S}_{(s)} + 2e \longrightarrow 2\text{Ag}_{(s)} + \text{S}^{2-}

is carried out in a half cell

\text{Pt}\,|\,\text{Ag}_2\text{S}/\text{Ag},\,\text{H}_2\text{S}\,(0.1\,\text{M})

, at

[\text{H}^+] = 10^{-3}

. The emf of a half cell is: [if

E_{\text{Ag}^+/\text{Ag}}^\circ = 0.80\,\text{V}

K_{a\,\text{H}_2\text{S}} = 10^{-21}

and

K_{sp}

\text{Ag}_2\text{S} = 10^{-49}

] (1)

-0.1735 \text{ V}

(2)

-0.19 \text{ V}

(3)

+0.1735 \text{ V}

(4)

+0.19 \text{ V}