Question

Which is the correct value for the standard potential for a silver-copper voltaic cell?
The standard half cell potential at $298K$ are:
$A{g}^{+}\left(aq\right)+e^{-}\to Ag\left(s\right);E_{red}^o=x$
$C{u}^{2+}\left(aq\right)+2e^{-}\to Cu\left(s\right):E_{red}^o=y$
[$x>y$]

• A. y - 2x
  
• B. x - y
• C. 2x + y
• D. x + 2y

Answer 1

The correct option is B x - y

The standard reduction potentials of half cells are
$E_{A{g}^{+}\left(aq\right)/Ag\left(s\right)}^{\circ }=xV$
$E_{C{u}^{2+}\left(aq\right)/Cu\left(s\right)}^{\circ }=yV$

$x>y$

Metal which having higher reduction potential will undergo reduction and metal having lower reduction potential will undergo oxidation.
Thus,
$A{g}^{+}$ is reduced to $Ag$ and $Cu$ is oxidised to $C{u}^{2+}$
$E_{cell}^{\circ }=\text{SRP of substance reduced}-\text{SRP of substance oxidised}$

$E_{cell}^{\circ }=E_{cathode\left(red\right)}^{\circ }-E_{anode\left(red\right)}^{\circ }$

$E_{cell}^{\circ }=E_{A{g}^{+}\left(aq\right)/Ag\left(s\right)}^{\circ }-E_{C{u}^{+}\left(aq\right)/Cu\left(s\right)}^{\circ }$

$E_{cell}^{\circ }=(x-y)V$

Thus, the correct answer is (c).