Question

One g of a mixture of ${Na}_{2}C{O}_3$ and $NaHC{O}_3$ consumes $y$ equivalent $HCl$ for complete neutralization. One g of the mixture is strongly heated, then cooled and the residue treated with $HCl$. How many equivalents of $HCl$ would be required for complete neutralization?

• A. $2y$ equivalent
• B. $y$ equivalent
• C. $\frac{3y}{4}$ equivalent
• D. $\frac{3y}{2}$ equivalent

Answer 1

The correct option is B $y$ equivalent

On heating, bicarbonates convert into carbonates while carbonates have no effect of heating.
$2NaHC{O}_3\stackrel{\Delta }{\to }{Na}_{2}C{O}_3+H_{2}O+C{O}_2$
${Na}_{2}C{O}_3\stackrel{\Delta }{\to }{Na}_{2}C{O}_3$
The number of equivalents of $NaHC{O}_3=$ Number of equivalents of ${Na}_{2}C{O}_3$ formed.
In solution same amount of base is present to react with acid so, same equivalent of $HCl$ will be used.