List of top Chemistry Questions asked in IISER

What is the order of bond energy between C=S & C=Te, and between Cl–Cl & F–F?

Metal-ligand $\pi$-bond formation in Mn$_2$(CO)$_{10}$ and [MnO$_4$]$^-$ requires electron-pair donation between metal and ligand orbitals. Which one of the following represents the direction of electron-pair donation?

Which one of the following molecules shows an increase in bond order after loss of an electron from the highest occupied molecular orbital?

What are the numbers of protons (H$^+$) and electrons (e$^-$), respectively, required for the reduction of [Cr$_2$O$_7$]$^{2-}$ to Cr$^{3+}$ under an aqueous acidic condition?

Which one of the following octahedral complexes has the highest spin-only magnetic moment?

During the charging and discharging of a lead-acid battery (a $\text{Pb}$ anode, a grid of $\text{Pb}$ packed with $\text{PbO}_2$ as cathode, and an aqueous solution of $\text{H}_2\text{SO}_4$ as an electrolyte), which of the following redox reactions does NOT occur?

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

What is the major product in the reaction sequence given below?

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

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 $\text{mol L}^{-1}\text{ min}^{-1}$. Which of the following plots is correct for this reaction?
[Note: $[\text{R}]_0$ is the initial concentration and $\text{t}_{1/2}$ is the half-life of the reaction]}

What is the time period of revolution of an electron in the fourth Bohr orbit of $\text{He}^+$?
(Bohr radius = 52.9 picometers, mass of an electron = $9.11 \times 10^{-31}\text{ kg}$, Planck’s constant = $6.626 \times 10^{-34}\text{ Js}$)}

Compound I undergoes hydroboration-oxidation reaction with $(\text{BH}_3)_2$ followed by treatment with $\text{H}_2\text{O}_2$ and aqueous $\text{NaOH}$ to produce another compound II, which upon oxidation with $\text{CrO}_3$ gives 2,3-dimethyl-cyclohexanone as the product. What is the structure of I?

What are the major products formed in the following reaction sequence?

Which of the following reactions do NOT provide an aldehyde as a product?

What is the value of $E^\circ(\text{Fe}^{3+}/\text{Fe}^0)$?
(The standard reduction potential values are $E^\circ(\text{Fe}^{3+}/\text{Fe}^{2+}) = 0.77\text{ V}$, and $E^\circ(\text{Fe}^{2+}/\text{Fe}^0) = -0.44\text{ V}$)}

What are the correct orders of stability for the following compounds?

Consider the following reaction scheme:

Which among the following statements is correct?

How many $\beta$-hydrogen is/are present in 2-methyl-3-phenyl-pentan-1-al?

Which among the following processes is/are associated with increasing bond order but no change in diamagnetic/paramagnetic behaviour?
(i) $\text{N}_2 \rightarrow \text{N}_2^+ + \text{e}^-$
(ii) $\text{O}_2 \rightarrow \text{O}_2^+ + \text{e}^-$
(iii) $\text{O}_2 + \text{e}^- \rightarrow \text{O}_2^-$

Which one of the following statements best describes the acidic/basic/amphoteric nature of ZnO and CaO?

Consider the following data for KCl solution at a particular temperature:

What is the value of the limiting molar conductivity?

Which one of the following plots correctly describes the variation of osmotic pressure (H) of a fixed amount of a solute against the volume (V) of the solution at a fixed temperature?

For a reaction R \(\longrightarrow\) P with a rate constant of 3 \(\times 10^{-3}\) mol L\(^{-1}\) s\(^{-1}\), which one of the following plots is correct?

The minimum energy needed to remove an electron from a metal corresponds to a wavelength of 500 nm. What is the total kinetic energy of all the photoelectrons ejected per second when the entire radiation from a 100 Watt bulb with a wavelength of 300 nm falls on the surface of the metal?
Planck’s constant = 6.6 \(\times 10^{-34}\) J s; speed of light = 3 \(\times 10^8\) m s\(^{-1}\)

Consider an exothermic reaction:
2A(s) \(\longrightarrow\) B(s) + C(g) + D(g)
The correct statement about the reaction is