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 neutralization. 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 $=\frac{1}{Ew}$

$\therefore Ew=\frac{1000}{20}=50g/equiv$