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प्रश्न
A first order reaction takes 40 min for 30% decomposition. Calculate t1/2.
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उत्तर
Given: Time (t) = 40 min
Let initial quantity = a
Decomposed quantity (x) = 30% of a = 0.30a
Remaining quantity = (a − x)
= a − 0.30a
= 0.70a
k = `2.303/t log a/(a - x)`
= `2.303/40 log a/(0.70 a)`
= `2.303/40 log 1.428`
k = 8.90 × 10−3 min−1
t1/2 = `0.693/k`
t1/2 = `0.693/(8.90 xx 10^-3)`
= 77.7 min
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