List of top Chemistry Questions on Molecular & Empirical Formula asked in JEE Main

Which of the following contain the same number of atoms? (Given : Molar mass in g mol\(^{-1}\) of H, He, O and S are \(1,4,16\) and \(32\) respectively)}

• [A.] \(2\,\text{g}\) of \(O_2\) gas
• [B.] \(4\,\text{g}\) of \(SO_2\) gas
• [C.] \(1400\,\text{mL}\) of \(O_2\) at STP
• [D.] \(0.05\,\text{L}\) of He at STP
• [E.] \(0.0625\,\text{mol}\) of \(H_2\) gas

Choose the correct answer from the options given below:

What volume of hydrogen gas at STP would be liberated by action of 50 mL of $H_2SO_4$ of 50% purity (density $= 1.3 \text{ g mL}^{-1}$) on 20 g of zinc?
Given : Molar mass of H, O, S, Zn are 1, 16, 32, 65 $\text{g mol}^{-1}$ respectively.

36 g of A reacts with 54 g of B to form AB\(_2\), if the molar mass of A and B is respectively 60 and 80, then choose the correct option from the following.

Consider the following data: \[ \text{Na(s)} + \frac{1}{2} \text{Cl}_2 \text{(g)} \rightarrow \text{NaCl(s)} \quad \Delta H^\circ = -411 \, \text{kJ/mole} \] \[ \text{Na(s)} \rightarrow \text{Na(g)} \quad \Delta H^\circ = 107 \, \text{kJ/mole} \] \[ \text{Cl}_2 \text{(g)} \rightarrow 2\text{Cl}(g) \quad \Delta H^\circ = 242 \, \text{kJ/mole} \] \[ \text{Cl(g)} + e^- \rightarrow \text{Cl}^-(g) \quad \Delta H^\circ = -355 \, \text{kJ/mole} \] \[ \text{Na(g)} \rightarrow \text{Na}^+(g) + e^- \quad \Delta H^\circ = 502 \, \text{kJ/mole} \] Find the lattice energy of NaCl(s).

Consider the statements below: Statement I: BCl\(_3\) is covalent in nature. Statement II: BCl\(_3\) undergoes hydrolysis to form [B(OH)\(_4\)]\(^{+}\) and BH\(_2^{+}\). In the light of the above statements, choose the correct option.

On complete combustion 1.0 g of an organic compound (X) gave 1.46 g of CO₂ and 0.567 g of H₂O. The empirical formula mass of compound (X) is:
(Given molar mass in g mol\(^{-1}\): C: 12, H: 1, O: 16)