1
NEET 2026
MCQ (Single Correct Answer)
+4
-1
Change Language

Given below is an expression for the rate constant of a first-order reaction occurring at a certain temperature, $\mathrm{T}(\mathrm{K})$.

$$ \operatorname{lnk}=14.34-\frac{1.25 \times 10^4}{T} $$

The energy of activation in $\mathrm{kcal} \mathrm{mol}^{-1}$ for the reaction is :

(Given: $\mathrm{k}^{-1} \mathrm{~s} \mathrm{~s}^{-1}, \mathrm{R}=1.987 \mathrm{cal} \mathrm{mol}^{-1} \mathrm{~K}^{-1}$ )

A

24.84

B

14.34

C

18.63

D

12.42

2
NEET 2025
MCQ (Single Correct Answer)
+4
-1
Change Language

If the rate constant of a reaction is $0.03 \mathrm{~s}^{-1}$, how much time does it take for $7.2 \mathrm{~mol} \mathrm{~L}^{-1}$ concentration of the reactant to get reduced to $0.9 \mathrm{~mol} \mathrm{~L}^{-1}$ ? (Given: $\log 2=0.301$ )

A
210 s
B
21.0 s
C
69.3 s
D
23.1 s
3
NEET 2025
MCQ (Single Correct Answer)
+4
-1
Change Language

If the half-life ( $t_{1 / 2}$ ) for a first order reaction is 1 minute, then the time required for $99.9 \%$ completion of the reaction is closest to :

A
5 minutes
B
10 minutes
C
2 minutes
D
4 minutes
4
NEET 2024 (Re-Examination)
MCQ (Single Correct Answer)
+4
-1
Change Language

Following data is for a reaction between reactants A and B :

Rate
$$\mathrm{mol} \mathrm{~L}^{-1} \mathrm{~s}^{-1}$$
$$\mathrm{[A]}$$ $$\mathrm{[B]}$$
$$
2 \times 10^{-3}
$$
0.1 M 0.1 M
$$
4 \times 10^{-3}
$$
0.2 M 0.1 M
$$
1.6 \times 10^{-2}
$$
0.2 M 0.2 M

$$ \text { The order of the reaction with respect to } \mathrm{A} \text { and } \mathrm{B} \text {, respectively, are } $$

A
1, 0
B
0, 1
C
1, 2
D
2, 1

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