Question

At 30ºC, the half life for the decomposition of \(AB_2\) is 200 s and is independent of the initial concentration of \(AB_2\). The time required for 80% of the \(AB_2\) to decompose is(Given : \(log\; 2 = 0.30,\; log \;3 = 0.48\))

• A. 200 s
• B. 323 s
• C. 467 s
• D. 532 s

Answer 1

The Correct Option is C

Since, half life is independent of the initial concentration of \(AB_2\).

Hence, reaction is “First Order”.

\(k =\frac{ 2.303 log\;2}{t_{1/2}}\)

\(\frac{2.303 log\;2}{t_{1/2}} = \frac{2.303}{t} \log\frac{100}{(100−80)}\)

\(\frac{2.303 \times 0.3 }{200} = \frac{2.303 }{ t }\log5\)

\(t = 467 \;s\)