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Question:

If mass of 5 mole AB₂ is 125 × 10⁻³kg and mass of 10 mol A₂B₂ is 300 × 10⁻³ kg. then correct molar mass of A and B respectively (in kg/mol)

A = 2.5 × 10⁻³ B = 5 × 10⁻³

A = 5 × 10⁻³ B = 25 × 10⁻³

A = 2.5 × 10⁻³ B = 10 × 10

A = 5 × 10⁻³ B = 10 × 10⁻³

Solution:

Correct option is D. A = 5 × 10⁻³ B = 10 × 10⁻³
Mass of 1 mol of AB₂ : M_A + 2M_B = 25 × 10⁻³ kg
Mass of 1 mol of A₂B₂: 2M_A + 2M_B = 30 × 10⁻³kg
∴ M_A = 5 × 10⁻³ kg / mol
M_B = 10 × 10⁻³kg/mol