5 moles of AB₂ weigh 125 × 10^–3 kg and 10 moles of A₂B₂ weigh 300 × 10^–3 kg. The molar mass of A (M_A) and molar mass of B (M_B) in kg mol are:

The mole fraction of a solvent in aqueous solution of a solute is 0.8. The molality (in mol kg^–1 ) of the aqueous solution is :

The minimum amount of O₂(g) consumed per gram of reactant is for the reaction :
(Given atomic mass : Fe = 56, O = 16, Mg = 24, P = 31, C = 12, H = 1)

At 300 K and 1 atmospheric pressure, 10 mL of a hydrocarbon required 55 mL of O₂ for complete combustion, and 40 mL of CO₂ is formed. The formula of the hydrocarbon is :