1
IAT (IISER) 2025
MCQ (Single Correct Answer)
+4
-1

The work done when one mole of an ideal gas expands at constant temperature $T$ from volume $V$ to $2 V$ (in two equal steps of volume in a linear fashion) is $\frac{7}{12} R T$. How much more work would be done by the gas if it expands in three equal steps?

[ $R$ is the universal gas constant]

A

$\frac{1}{30} \mathrm{R} T$

B

$\frac{3}{8} \mathrm{R} T$

C

$\frac{3}{4} \mathrm{R} T$

D

$-\mathrm{R} T \ln \left(\frac{1}{15}\right)$

2
IAT (IISER) 2025
MCQ (Single Correct Answer)
+4
-1

At a particular temperature, the magnitude of the rate constant of a reaction is $5 \times 10^{-5}$ and the unit of the pre-exponential factor of the Arrhenius equation for this reaction is $\mathrm{mol} \mathrm{L}^{-1} \mathrm{~min}^{-1}$. Which of the following plots is correct for this reaction?

$\left[\right.$ Note: $[\mathrm{R}]_0$ is the initial concentration and $t_{1 / 2}$ is the half-life of the reaction $]$

A
IAT (IISER) 2025 Chemistry - Chemical Kinetics Question 1 English Option 1
B
IAT (IISER) 2025 Chemistry - Chemical Kinetics Question 1 English Option 2
C
IAT (IISER) 2025 Chemistry - Chemical Kinetics Question 1 English Option 3
D
IAT (IISER) 2025 Chemistry - Chemical Kinetics Question 1 English Option 4
3
IAT (IISER) 2025
MCQ (Single Correct Answer)
+4
-1

What is the time period of revolution of an electron in the fourth Bohr orbit of $\mathrm{He}^{+}$?

[Bohr radius $=52.9$ picometers, mass of an electron $=9.11 \times 10^{-31} \mathrm{~kg}$, Planck's constant $=6.626 \times 10^{-34} \mathrm{Js}$ ]

A

24 femtoseconds

B

4.8 femtoseconds

C

24 femtoseconds

D

2.4 femtoseconds

4
IAT (IISER) 2025
MCQ (Single Correct Answer)
+4
-1

The dipole moments of three $\mathrm{AB}_3$-type molecules $\mathbf{I}, \mathbf{I I}$, and $\mathbf{I I I}$ are measured to be $0.0 \mathrm{D}, 0.2 \mathrm{D}$, and 1.5 D , respectively. Which one of the following options is correct regarding the identity of $\mathbf{I}, \mathbf{I I}$, and $\mathbf{I I I}$ ?

A

I: $\mathrm{BF}_3, \mathbf{I I}: \mathrm{NF}_3, \mathbf{I I I}: \mathrm{NH}_3$

B

I: $\mathrm{BF}_3, \mathbf{I I}: \mathrm{NH}_3, \mathbf{I I I}: \mathrm{NF}_3$

C

I: $\mathrm{ClF}_3, \mathbf{I I}: \mathrm{NF}_3, \mathbf{I I I}: \mathrm{NH}_3$

D

I: $\mathrm{BCl}_3, \mathbf{I I}: \mathrm{NH}_3, \mathbf{I I I}: \mathrm{NF}_3$

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