MHT CET 2025 22nd April Morning Shift | Chemical Kinetics Question 10 | Chemistry

Half life of a first order reaction is 20 minutes. The time taken to reduce the initial concentration of reactant to $(1 / 10)^{\text {th }}$ is _________

46.60 min

66.46 min

79.68 min

88.00 min

MHT CET 2025 21st April Evening Shift

MCQ (Single Correct Answer)

-0

Rate law for the reaction $a A+b B \rightarrow c C+d D$ is $\mathrm{r}=\mathrm{k}[\mathrm{A}][\mathrm{B}]$. Which from following conditions does NOT affect the rate of reaction?

Concentration of A is doubled and concentration of $B$ is kept constant.

Concentration of B is doubled and concentration of $A$ is kept constant.

Concentration of B is doubled and concentration of $A$ is halved.

Concentration of A is kept constant and concentration of $B$ is halved.

MHT CET 2025 21st April Evening Shift

MCQ (Single Correct Answer)

-0

Nitric oxide reacts with $\mathrm{H}_2$ according to reaction, $2 \mathrm{NO}_{(\mathrm{g})}+2 \mathrm{H}_{2(\mathrm{~g})} \longrightarrow \mathrm{N}_{2(\mathrm{~g})}+2 \mathrm{H}_2 \mathrm{O}_{(\mathrm{g})}$, identify the correct relationship among the following.

$-\frac{1}{2} \frac{\mathrm{~d}[\mathrm{NO}]}{\mathrm{dt}}=\frac{\mathrm{d}\left[\mathrm{H}_2 \mathrm{O}\right]}{\mathrm{dt}}$

$-\frac{\mathrm{d}[\mathrm{NO}]}{\mathrm{dt}}=\frac{\mathrm{d}\left[\mathrm{H}_2 \mathrm{O}\right]}{\mathrm{dt}}$

$-\frac{3}{2} \frac{\mathrm{~d}[\mathrm{NO}]}{\mathrm{dt}}=\frac{\mathrm{d}\left[\mathrm{H}_2 \mathrm{O}\right]}{\mathrm{dt}}$

$\quad 2 \frac{\mathrm{~d}\left[\mathrm{H}_2\right]}{\mathrm{dt}}=\frac{\mathrm{d}\left[\mathrm{N}_2\right]}{\mathrm{dt}}$

MHT CET 2025 21st April Evening Shift

MCQ (Single Correct Answer)

-0

For a reaction, $\mathrm{A} \longrightarrow \mathrm{B}$, rate equation is $\mathrm{r}=\mathrm{k}[\mathrm{A}]^{\circ}$. If initial concentration of reactant is 'a'mol dm ${ }^{-3}$ find half life time of reaction.

$\frac{\mathrm{a}}{4 \mathrm{k}}$

$\frac{\mathrm{a}}{\mathrm{k}}$

$\frac{5 \mathrm{a}}{2 \mathrm{k}}$

$\frac{\mathrm{a}}{2 \mathrm{k}}$

PREVIOUS NEXT

MHT CET Subjects