Question

$4\, g$ of hydrogen react with $9.023 \times 10^{23}$ molecules of chlorine to form $HCl$ gas. The total pressure after the reaction was found to be $700\, mm$. The partial pressure of $HCl$ will be

• A. 3900 mm
• B. 600 mm
• C. 700 mm
• D. 350 mm

Answer 1

Answer: (B)

$3 / 2$ mol of $Cl _{2}$ will react with $3 / 2$ mol of $H _{2}$ to give$\frac{3}{2} \times 2=3.0\, mol$ of $HCl$. So the total number of moles in the reaction

$=\left(2-\frac{3}{2}\right)+0+3=3.5$

Partial pressure of $HCl =\frac{3 \times 700}{3.5}=600$ mm