Question

$1$ g of the carbonate of a metal was dissolved in $25$ mL of $1N$ $HCl$. The resulting liquid required $5$ mL of $1N$ $NaOH$ for neutralisation. The Equivalent weight of the metal carbonate is:

• A. 50
• B. 30
• C. 20
• D. none

Answer 1

The correct option is A 50

Total $HCl\Rightarrow 25\times 1=25$ mEq
Excess $HCl\Rightarrow 5\times 1=5$ mEq
$HCl$ used $\Rightarrow 25-5=20$ mEq

$\therefore$ mEq of $HCl$ $=$ mEq of carbonate

$\frac{20}{1000}Eq=\frac{Weight}{Ew}$ of carbonate $=\frac{1}{Ew}$

$\therefore Ew=\frac{1000}{20}=50$