If sodium sulphate is considered to be completely dissociated into cations and anions in aqueous sol — Solutions and Colligative Properties Chemistry Question
Question
If sodium sulphate is considered to be completely dissociated into cations and anions in aqueous solution, the change in freezing point of water fT , when 0.01 mole of sodium sulphate is dissolved in 1 kg of water, is (kf = 1.86 K Kg mol–1) (2010)
💡 Solution & Explanation
2 2 4 4 2 Na SO Na SO -> Vant Hoff factor for 2 4 3 Na SO Hence, 0.01 3 1.86 0.0558 1 f f f T iK m T K x x 136. The elevation in boiling point of a solution of 9.43g of MgCl2 in 1 kg of water is (Kb = 0.52 K kg mol–1, Molar mass of MgCl2=94.3g mol–1) (a) 0.156 (b) 0.52 (c) 0.17 (d) 0.94 ? b T 0.52 / b K k mg mole MgCl2=Mg2+ + 2Cl- 1000 b B b B A k W i T M W x x x x Or 9.43 3 0.52 94.3 0.156 b b b T i K m T x x x x 137. What amount of CaCl2 (i = 2.47) is dissolved in 2 litres of water so that its osmotic pressure is 0.5 atm at 27ºC? (a) 3.42 g (b) 9.24 g (c)