Question

$2.5g$ of the carbonate of metal was treated with $100ml$ of $1N$ $H_2{SO}_4$. After the completion of the reaction, the solution was boiled off to expel ${CO}_2$ and was then titrated against $1N$ $NaOH$ solution. The volume of alkali that would be consumed, if the equivalent weight of the metal is $20$ is :

• A. $50$
• B. $25$
• C. $75$
• D. $100$

Answer 1

The correct option is A $50$

Equivalent weight of metal carbonate $=20+30=50$
$2.5g$ of metal carbonate $=\frac{2.5}{50}eq$
Number of equivalent of $H_{2}S{O}_4$ would have reacted $=0.05$
Number of equivalent of $H_2{SO}_4$ taken
$=\frac{100\times 1}{1000}=0.1$
Number of equivalent of $H_2{SO}_4$ remains unreacted $=0.1-0.05=0.05eq.$
$\therefore$ Number of equivalent of alkali consumed $=0.05eq.$
milli eq.$=$ Normality $\times$ Volume in ml
$\therefore$ $1.0\times V=0.05\times 1000$
$V=\frac{0.05\times 1000}{1.0}=50ml$