Question

Number of $K^{+}$ ions and number of moles of $K^{+}$ ions present in $1L$ of $\frac{N}{5}KMn{O}_4$ solution respectively, in acidic medium are :

• A. $0.04$ and $2.4\times {10}^{22}$
• B. $2.4\times {10}^{22}$ and $0.04$
• C. $200$ and $6.023\times {10}^{23}$
• D. $6.023\times {10}^{23}$ and $200$

Answer 1

The correct option is B $2.4\times {10}^{22}$ and $0.04$

Number of moles in one litre of $\frac{N}{5}KMn{O}_4$ solution $=\frac{Normality}{n_f}=\frac{1}{5\times 5}=\frac{1}{25}=0.04mol$.

So, no. of moles of $K^{+}=0.04mol$ and number of $K^{+}=N_A\times 0.04=2.4\times {10}^{22}$.