List of top Chemistry Questions

An organic compound 'A' has the molecular formula \( C_3H_6O \), it undergoes iodoform test. When saturated with dil. HCl it gives 'B' of molecular formula \( C_9H_{14}O \). A and B respectively are:

A reaction involving \( K_2 \text{Cr}_2 \text{O}_7 \) is treated with hydrogen sulfide. The oxidation number of chromium changes from +3 to +6, +2, or remains unchanged. Which of the following correctly reflects the change in oxidation number?

At low pressure, the van der Waals equation is reduced to:

In a closed insulated container, a liquid is stirred with a paddle to increase its temperature. In this process, which of the following is true?

For the reaction \[ \text{H}_2 \text{(g)} + \frac{1}{2} \text{O}_2 \text{(g)} \rightarrow \text{H}_2 \text{O}(\ell), \Delta H = -285.8 \, \text{kJ/mol}^{-1} \] \text{The value of free energy change at 27°C for the reaction is:}

Bragg's law is given by which of the following equation?

Copper sulfate solution reacts with KCN to give:

Deep sea divers use to respire a mixture of:

The value of \( K_c \) for the reaction: \[ A + 3B \rightleftharpoons 2C \text{ at } 400^\circ C \text{ is } 0.5. \text{ Calculate the value of } K_p. \]

What is X in the following change?

Ethylene glycol, on oxidation with periodic acid, gives:

The wavelengths of two photons are 2000Å and 4000Å, respectively. What is the ratio of their energies?

The electrode potentials for \[ \text{Cu}^{2+}(aq) + e^- \rightleftharpoons \text{Cu}(s) \] \text{and} \[ \text{Cu}^{2+}(aq) + e^- \rightleftharpoons \text{Cu}(aq) \] \text{are +0.15 V and +0.50 V, respectively. The value of \( E^\circ_{\text{Cu}^{2+}/\text{Cu}} \) will be:}

Tautomerism is net exhibited by:

Acidified potassium dichromate is treated with hydrogen sulfide. In the reaction, the oxidation number of chromium:

A Fischer projection of (2R, 3S)-2,3-butanediol is:

The work done in ergs for the reversible expansion of one mole of an ideal gas from a volume of 10 litres to 20 litres at 25°C is:

Arrange the following particles in increasing order of values of \( e/m \) ratio: electron (e), proton (p), neutron (n) and \( \alpha \)-particle (\( \alpha \)):

For the reaction \( N_2 + 3H_2 \rightarrow 2NH_3 \), if \( \frac{\Delta [NH_3]}{\Delta t} = 2 \times 10^{-4} \, \text{mol L}^{-1} \text{s}^{-1} \), then the value of \( \frac{\Delta [H_2]}{\Delta t} \) would be:

\(BrO^{3-}\) Changes into \(Br_2\) in an acidic medium of a unbalanced equation how many electron should be present on the balanced electron.

The most stable carbocation, among the following is :-

The IUPAC symbol for the element with atomic number $119$ would be :

Mendeleeff's periodic table is based on

Total number of elements in Newland's periodic table is