Question

Assertion :$HCl$ gas can be dried by passing through $P_2{O}_5$. Reason: $P_2{O}_5$ reacts with $HCl$ to form $POC{l}_3$ and $HP{O}_3$.

• A. If both assertion and reason are CORRECT and reason is the CORRECT explanation of the assertion.
• B. If both assertion and reason are CORRECT, but reason is NOT THE CORRECT explanation of the assertion.
• C. If assertion is CORRECT, but reason is INCORRECT.
• D. If assertion is INCORRECT, but reason is CORRECT.

Answer 1

The correct option is C If assertion is CORRECT, but reason is INCORRECT.

A wet gas can be dried by removing water from it.
For assertion:
$6HCl$ + $P_2{O}_5\to 2POC{l}_3$ + $3H_{2}O$
So, we need excess $P_2{O}_5$ to remove the water.
$P_2{O}_5$ + $3H_{2}O\to 2H_{3}P{O}_4$
The water formed from reaction of HCl gas and $P_2{O}_5$ will not destroy any or all $POC{l}_3$ formed.
As shown in the above reaction HCl reacts with $P_2{O}_5$ form $POC{l}_3$ and water.
Thus reason is incorrect.
Option C.