1
JEE Main 2023 (Online) 25th January Evening Shift
Numerical
+4
-1

A first order reaction has the rate constant, $$\mathrm{k=4.6\times10^{-3}~s^{-1}}$$. The number of correct statement/s from the following is/are __________

Given : $$\mathrm{\log3=0.48}$$

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 ($$\mathrm{1-e^{-kt}}$$)

E. The rate and the rate constant have the same unit.

2
JEE Main 2023 (Online) 25th January Morning Shift
Numerical
+4
-1

For the first order reaction A $$\to$$ B, the half life is 30 min. The time taken for 75% completion of the reaction is _________ min. (Nearest integer)

Given : log 2 = 0.3010

log 3 = 0.4771

log 5 = 0.6989

3
JEE Main 2023 (Online) 24th January Morning Shift
Numerical
+4
-1

The number of correct statement/s from the following is __________

A. Larger the activation energy, smaller is the value of the rate constant.

B. The higher is the activation energy, higher is the value of the temperature coefficient.

C. At lower temperatures, increase in temperature causes more change in the value of k than at higher temperature

D. A plot of $$\mathrm{\ln k}$$ vs $$\frac{1}{T}$$ is a straight line with slope equal to $$-\frac{E_a}{R}$$

4
JEE Main 2022 (Online) 29th July Evening Shift
Numerical
+4
-1

Assuming $$1 \,\mu \mathrm{g}$$ of trace radioactive element X with a half life of 30 years is absorbed by a growing tree. The amount of X remaining in the tree after 100 years is ______ $$\times\, 10^{-1} \mu \mathrm{g}$$.

[Given : ln 10 = 2.303; log 2 = 0.30]