1
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0

Two statements, One Assertion (A) and the other Reason (R) are given. Choose the right option.

Assertion: The rate constant $(\mathrm{k})$ for a chemical reaction gets nearly doubled for a $10^0$ rise in temperature.

Reason: The number of bimolecular collisions between reactant molecules increase with increase in temperature

A
A is correct but R is wrong.
B
Both A and R are correct but R is not the correct explanation of A .
C
Both $A$ and $R$ are correct and $R$ is the correct explanation of $A$.
D
A is wrong but R is correct.
2
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0
Two chemical reactions of the same order have equal Frequency factor value. Their Activation energies differ by $26.8 \mathrm{~kJ} / \mathrm{mol}$. At 300 K if $k_2=x k_1$ find the value of $x$.
A
$4.631 \times 10^4$
B
$1.143 \times 10^3$
C
$2.286 \times 10^3$
D
4.665
3
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0
For a given reaction of the type $\frac{3}{5} X(a q) \rightarrow \frac{1}{2} Y(a q)+Z(g)$, the correct expression for the rate of disappearance of $X$ with reference to $Y$ is ___________
A
$-d \frac{[X]}{d t}=+\frac{6}{5} d \frac{[Y]}{d t}$
B
$-d \frac{[X]}{d t}=+\frac{5}{6} d \frac{[Y]}{d t}$
C
$-d \frac{[X]}{d t}=+\frac{3}{10} d \frac{[Y]}{d t}$
D
$-d \frac{[X]}{d t}=d \frac{[Y]^{1 / 2}}{d t}$
4
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0
$\mathrm{X} \rightarrow 2 \mathrm{Y}$ is a first order reaction where $1.0 \mathrm{~mol} / \mathrm{L}$ of the reactant yields $0.4 \mathrm{~mol} / \mathrm{L}$ of Y in 200 minutes. Calculate the half-life period of the reaction in minutes.
A
151.24
B
203.69
C
620.96
D
271.34
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