Question

Find the n-factor of Cu and Zn for reduction of copper sulphate by Zinc ?

• A. 2,2
• B. 1,2
• C. 2, 1
• D. 0, 0

Answer 1

The correct option is A 2,2

Steps for finding valency factor/n-factor:
1. Find the oxidation state (O.S.) of metal in reactant side.
2. Find the oxidation state of metal in product side.
3. Take the magnitude of difference of two oxidation state $|O.S{.}_{Product}-O.S{.}_{Reactant}|\times \text{number of atom}$ for the valency factor
the reduction reaction is given by $Zn+CuS{O}_4\to ZnS{O}_4+Cu$
O.S. of Zn in reactant side=0
O.S. of Zn in product side
$x-2=0$
$x=+2$
$\text{valency factor}=\text{number of Zn atom}\times |O.S{.}_{Product}-O.S{.}_{Reactant}|$
$\text{valency factor}=1\times |+2-0|$
$\text{valency factor}=2$

O.S. of Cu in reactant side
$x-2=0$
$x=+2$
O.S. of Cu in product side=0
$\text{valency factor}=\text{number of Cu atom}\times |O.S{.}_{Product}-O.S{.}_{Reactant}|$
$\text{valency factor}=1\times |0-2|$
$\text{valency factor}=2$