Question

In the synthesis of ammonia from nitrogen and hydrogen gases, if $6\times 10^{-2}$ moles of hydrogen disappears in $10$ minutes, the number of moles of ammonia formed in $3$ minutes is

• A. $1.8\times 10^{-2}$
• B. $1.2\times {10}^{-2}$
• C. $4.0\times {10}^{-2}$
• D. $3.6\times {10}^{-2}$

Answer 1

Answer: (B)

$\because$ In $10$ min, the number of $H_2$ disappears $=6\times 10^{-2}$
$\therefore$ In $3$ min, the number of moles of $H_2$
disappears $=\frac{6\times 10^{-2}\times 3}{10}$
$=1.8\times 10^{-2}$
$N_2+3H_2\rightleftharpoons 2N{H}_3$
$\Rightarrow \frac{1}{3}[$ Rate of disappearance of $H_2]$
$=\frac{1}{2}[$ Rate of formation of $N{H}_3]$
$\therefore$ Rate of formation of $N{H}_3=\frac{2}{3}\times 1.8\times 10^{-2}$
$=1.2\times 10^{-2}$ mol $N{H}_3$
$\therefore 1.2\times 10^{-2}$ moles of $N{H}_3$ are formed.