Question

The $pH$ of the resultant solution obtained by mixing $20mL$ of $0.01M \,HCl$ and $20mL$ of $0.005M \,Ca(OH)_2$ is

• A. $2$
• B. $0$
• C. $1$
• D. $7$
• E. $5$

Answer 1

Answer: (D)

$Ca ( OH )_{2}+2 HCl \rightarrow CaCl _{2}+2 H _{2} O$
$n=0.005 \times \frac{20}{1000} 0.01 \times \frac{20}{1000}$
$1 \times 10^{-4} 2 \times 10^{-4}$
$1 mol Ca ( OH )_{2} \rightarrow 2 mol HCl$
$1 \times 10^{-4} mol \,Ca ( OH )_{2} \rightarrow 2 \times 10^{-4} mol\, HCl HCl$
Solution is neutral in nature
$p H =7$