Question

When $10$ mL of hydrogen and $12.5$ mL of chlorine are allowed to react, the final mixture contains:

• A. $22.5$ mL of $HCl$
• B. $12.5$ mL of $HCl$
• C. $20$ mL of $HCl$ and $2.5$ mL of chlorine
• D. $20$ mL of $HCl$ only

Answer 1

The correct option is C $20$ mL of $HCl$ and $2.5$ mL of chlorine

Assuming STP conditions, $10$ mL of hydrogen and $12.5$ mL of chlorine corresponds to $0.45$ and $0.55$ millimoles of hydrogen and chlorine respectively.

The reaction is $H_2+{Cl}_2\to 2HCl$

Thus, $1$ mole of hydrogen reacts with $1$ mole of chlorine to form two moles of $HCl$.

$0.45$ millimoles of hydrogen will react with $0.45$ millimoles of chlorine to form $0.9$ millimoles of $HCl$.

$0.1$ millimoles of chlorine will remain unreacted.

Thus, the reaction mixture will contain $0.10$ millimoles of chlorine and $0.9$ millimoles of $HCl$.

At STP, this corresponds to $20.16$ mL of $HCl$ and $2.24$ mL of chlorine.