Question

Calculate the standard emf of a cell that uses the Mg/Mg2+ and Cu/Cu2+ half-cell reaction at 25°C. E o = V Write the equation for the cell reaction that occurs under standard-state conditions. Be sure to include the physical state of each species in the reaction.

Answer 1

Answer with Explanation:

We have to calculate the standard emf of a cell.

Consider $E^0_{Mg/Mg+2}=-2.37 v$

$E^0_{Cu/Cu+2}=0.34 V$

T=$25^{\circ}=25+273=298 K$

Anode half reaction:$Mg(s)\rightarrow Mg+2(aq)^+2e-$

Cathode half reaction:$Cu+2(aq)+2e-\rightarrow Cu(s)$

Overall reaction of cell :

$Mg(s)+Cu+2(aq)\rightarrow Mg+2(aq)+Cu(s)$

Cathode :The electrode which gains electrons.

Anode: The electrode  which losses electrons.

We know that standard emf of the cell

$E^0_{cell}=E_{cathod}-E_{Anode}$

$E^0_{cell}=0.34+2.37=2.71 V$

Hence, the standard emf of  a cell=2.71 V