Question

Equal volumes of three acid solutions of pH 3, 4 and 5 are mixed in a vessel. What will be the $H^{+}$ concentration in the mixture?

• A. $3.7\times {10}^{-3}M$
• B. $1.11\times {10}^{-3}M$
• C. $1.11\times {10}^{-4}M$
• D. $3.7\times {10}^{-4}M$

Answer 1

The correct option is D

$3.7\times {10}^{-4}M$

$\left[H^{+}\right]={10}^{-3}M,\left[H^{+}\right]={10}^{-4}M,\left[H^{+}\right]={10}^{-5}M\text{for the given acids}M=\frac{M_1{V}_1+M_2{V}_2+M_3{V}_3}{V}\therefore V_1=V_2=V_3,V_1+V_2+V_3=V=\left[\right({10}^{-5}\times 1)+({10}^{-4}\times 1)+({10}^{-3}\times 1\left)\right]÷3=3.7\times {10}^{-4}M$