All India Engineering / Architecture Entrance Examination (AIEEE)

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AIEEE 2007 Chemistry

Q. 16. . A 5.25% solution of a substance is isotonic with a 1.5% solution of urea (molar mass = 60 g mol^–1) in the same solvent. If the densities of both the solutions are assumed to be equal to 1.0 g cm–3, molar mass of the substance will be

1. 90.0 g mol^–1
2. 115.0 g mol^–1
3. 105.0 g mol^–1
4. 210.0 g mol^–1

Sol: Since the two solutions are isotonic, their concentrations will be same. Correct choice: (4)

Q. 17. Assuming that water vapour is an ideal gas, the internal energy change when 1 mol of water is vapourised at 1 bar pressure and 100⁰C,(Given: Molar enthalpy of vapourisation of water at 1 bar and 373 K = 41 kJ mol⁻¹ and R = 8.3 J mol⁻¹K⁻¹) will be:

1. 4.100 kJ mol−1
2. 3.7904 kJ mol−1
3. 37.904 kJ mol−1
4. 41.00 kJ mol−1

Sol:

Correct choice: (3)

Q. 18. In a saturated solution of the sparingly soluble strong electrolyte AgIO₃(Molecular mass = 283) the equilibrium which sets in is If the solubility product constant K spof AgIO₃ at a given temperature is, what is the mass of AgIO₃contained in 100 ml of its saturated solution?

1. 28.3 × 10^–2 g
2. 2.83 × 10^–3 g
3. 1.0 × 10^–7 g
4. 1.0 × 10^–4 g

Sol:

If ‘s’ is the solubility of AglO₃ in a saturated solution, then

Correct choice: (2)