Question

Which of the following are used as drying agent during the preparation of $HCl$ from the $NaCl$ and $H_{2}S{O}_4$?

• A. Phosphorus pentoxide ($P_2{O}_5$)
• B. Calcium oxide ($CaO$)
• C. Both $A$ and $B$
• D. None of the above

Answer 1

The correct option is D None of the above

$\text{Drying agents:}$ Dry hydrogen chloride is collected by bubbling through conc. $H_{2}S{O}_4$.

$\text{Reason for not using}$ $P_2{O}_5$ $\text{and CaO drying agents:}$

Other drying agents like $P_2{O}_5$ and $CaO$ are not used because they react with $HCl$
$2HCl+CaO\to CaC{l}_2+H_{2}O$
$3HCl+P_2{O}_5\to POC{l}_3+3HP{O}_3$

Option D is correct.