Question

Calculate the rate constant for decomposition of ammonium nitrite from the following.

Time (minutes)	$10$	$20$	$\infty$
Vol. of $N_2$(ml)	$6.25$	$13.65$	$35.05$

$N{H}_{4}N{O}_2\to N_2+2H_{2}O$
[Given that the reaction follows first order kinetics]

• A. $0.0197$ $mi{n}^{-1}$
• B. $1.97$ $mi{n}^{-1}$
• C. $0.197$ $mi{n}^{-1}$
• D. None of these

Answer 1

Answer: (A)

$0.0197$ $mi{n}^{-1}$

Since reaction is first order so value of rate constant at different value of volume
So $⟹k1=\frac{1}{t}\ln \frac{V_{\infty }}{V_{\infty }-V_t}$
At time 10 sec$⟹k1=\frac{1}{10}\ln \frac{35.05}{28.60}$
$⟹0.0197mi{n}^{-1}$