List of top Chemistry Questions

Choose the incorrect statement from the following.

Choose the incorrect statement.

For a hypothetical chemical reaction \( A_2 + 3B_2 \rightarrow 2AB_3 + \text{Heat} \), which one of the following combinations of state variables would support the spontaneity of the reaction at a particular temperature?

Which one of the following compounds will give a yellow precipitate when reacted with \( I_2/\text{NaOH} \)?

Identify X and Y formed in the following two reactions.
\[ (i) \, \text{Decan-1-ol} \xrightarrow{\text{Jones reagent}} X \]
\[ (ii) \, \text{Sodium salt of X} \xrightarrow{\text{NaOH/CaO,} \Delta} Y \]

Larger number of oxidation states are exhibited by the actinoids than those of lanthanoids. The reason is:

From among the 4 given compounds identify the compounds which possess a net dipole moment.

Which one of the following is incorrect?

Given below are 2 statements: one Assertion and the other Reason. Which of the following options is correct?
Assertion: Sulphur dioxide and Hydrogen peroxide can act as both oxidising and reducing agents but Nitric acid can act as only an oxidising agent.
Reason: Sulphur and Oxygen can exhibit more than one stable oxidation states while Nitrogen does not.

Which is the correct order of increasing number of unpaired electrons in the following ions?
\( A = \text{Cr}^{2+} \, (Z = 24), \quad B = \text{Cu}^{2+} \, (Z = 29), \quad C = \text{Ni}^{2+} \, (Z = 28), \quad D = \text{Fe}^{3+} \, (Z = 26) \)

A dilute solution of \( K_2HgI_4 \) reagent is 95% ionised. What would be the approximate value of its van't Hoff factor?

The hydrogenation of Ethyne is carried out at 600 K. The same reaction when carried out in the presence of a catalyst maintaining the same rate constant, the temperature required is only 400 K. If the catalyst lowers the Activation energy of the reaction by 20 kJ/mol, what is the value of \( E_a \)?

Complete the following 2 reactions A & B by choosing appropriate reactants [X] & [Y].

The time needed for completion of 80% is \( y \) times the half-life period of a first order reaction. What is the value of \( y \)?

What would be the cell potential for the Galvanic cell which is represented by the electrochemical reaction: \[ 2 \text{Cr(s)} + 3 \text{Fe}^{2+} (0.02M) \rightarrow 2 \text{Cr}^{3+} (0.2M) + 3 \text{Fe} \] \[ E^{0}_{\text{Fe}^{2+}/\text{Fe}} = -0.42 \, \text{V}, \quad E^{0}_{\text{Cr}^{3+}/\text{Cr}} = -0.72 \, \text{V} \]

Choose the statements which are incorrect in the case of Lanthanoids.

An aqueous solution which contains 42% by weight (w/W) of a volatile liquid "A" of molar mass of 140 g/mol, has a vapour pressure of 2141.4 mm of Hg at 37°C. What is the vapour pressure of the pure liquid "A"? Vapour pressure of water at 37°C is 2019.1 mm.

A current of 1.5 A is passed for 2 hours through an aqueous solution of PdX\(_n\), where X is a monovalent anion. During the electrolysis process 2.977 g of Palladium metal gets deposited at the cathode. Calculate the charge on Pd ions. (Atomic mass of Pd = 106.4 g/mol).

Which of the following is the correct name according to IUPAC rules?

Lead storage battery contains 4.25 M \( \text{H}_2\text{SO}_4 \) which has a density of 1.24 g/ml. Calculate the molality of the aqueous solution of \( \text{H}_2\text{SO}_4 \).

The ionisation constant of the weak acid HF whose concentration is 0.1 M is \( 3.5 \times 10^{-4} \). The equilibrium constant value for the reaction
\[ \text{F}^- + \text{H}_2\text{O} \leftrightarrow \text{HF} + \text{OH}^- \]
is ............ and the pH of the aqueous solution of the weak acid is ...............

An Alkene "X" on reaction with hot acidified \( \text{KMnO}_4 \) gave a mixture of Ethanoic acid and Propanone. Identify "X".

The Enthalpy of combustion of 1.0 mole of a reactive metal X at \( 27^\circ C \) and 1.0 bar pressure to form a solid oxide (XO) is -601.83 kJ/mol. The internal energy change for this reaction is --------- kJ. \[ R = 8.314 \, \text{J K}^{-1} \text{mol}^{-1} \]

Given are 4 pairs of covalent molecules. Identify the pair in which both molecules have the same shape.

An organic compound A (C\(_5\)H\(_9\)N) upon reaction with Na/Hg/C\(_2\)H\(_5\)OH gives compound B. B reacts with NaNO\(_2\)/HCl at 274 K to form C with quantitative liberation of N\(_2\) gas. B also reacts with Hinsberg's reagent to form a compound which is soluble in alkali. Identify compound B.