JEE Mains · Chemistry · STD 12 - 3. Chemical kinetics
For a first order reaction \(A \rightarrow B\)
| \(t/\text{min}\) | \([A]/M\) |
|---|---|
| \(0\) | \(0.6500\) |
| \(x\) | \(0.0650\) |
| \(20\) | \(0.00065\) |
\(x=\) ______ min. (Nearest integer)
- A 4
- B 5
- C 6
- D 7
Answer & Solution
Correct Answer
(D) 7
Step-by-step Solution
Detailed explanation
For a first order reaction, the rate constant \(k\) is given by: \(k = \dfrac{1}{t} \ln \dfrac{[A]_0}{[A]_t}\) Using the data at \(t = 20\) min: \(k = \dfrac{1}{20} \ln \dfrac{0.6500}{0.00065} = \dfrac{1}{20} \ln 1000 = \dfrac{3}{20} \ln 10\) Using the data at \(t = x\) min:…
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