• # question_answer The normality of solution obtained by mixing 10 ml of $\frac{N}{5}HCl$ and 30 ml of $\frac{N}{10}HCl$ is A)  $\frac{N}{5}$                                  B) $\frac{N}{8}$C) $\frac{N}{15}$                                 D) $\frac{N}{7.5}$

The normality of mixture is as follows: ${{N}_{1}}{{V}_{1}}+{{N}_{2}}{{V}_{2}}+{{N}_{3}}{{V}_{3}}....=Nr\,Vr$ $\frac{N}{5}\times 10+\frac{N}{10}\times 30=Nr\times 40$ $2N+3N=40\,Nr$ $5N+3N=40\,Nr$ $Nr=\frac{5N}{40}=\frac{N}{8}$ Hence, the correct option is [b].