Question

A first order reaction has the rate constant, $k =46 \times 10^{-3} s ^{-1}$ The number of correct statement/s from the following is/are _______
Given: $\log 3=0.48$
A. Reaction completes in $1000 \,s$
B. The reaction has a half-life of $500 \, s$
C. The time required for $10 \%$ completion is 25 times the time required for $90 \%$ completion
D. The degree of dissociation is equal to $\left(1-e^{-k t}\right)$
E. The rate and the rate constant have the same unit

Answer 1

The correct answer is 2.
t10%​=K1​ln(a−xa​)=K1​ln(90100​)
t10%​=K2.303​(log10−log9)
t10%​=K2.093​×(0.04)
Similarly
t90%​=K1​ln(10100​)
t90%​=K2.303​
t10%​t90%​​=0.041​=25
ekt=a−xa​
aa−x​=e−kt
1−ax​=e−kt
x=a(1−e−kt)
α=ax​=(1−e−kt)