Set 15 Chemistry [Paper] 2

1 SECTION A (60 Marks) Answer only three questions from this section . 1. Complete the following equations and outline the mechanisms . a).CH3COCH3 + NaHSO3 ............................. (03 marks) b).CH3CH2COOH ............................. (04½ marks) c).CH3CH2Br ............................. (02 marks) d). ............................ (04½ marks) e). ............................ (03 marks) f). ............................ (03 marks)OHO CH3 Conc.H2SO4 HeatCH3CH2OH NaOH/HeatH2NNHCONH2/H+CH3CH2OK+/C2H5OH HeatH+/CH3CH2OH 2. Water boils at 100 ᵒC and a pressure at 101.3kPa. Aminobenzene boils at 112ᵒC.A mixture of water and aminobenzene boils at 96 ᵒC. a. Explain the above observation. (05 mark s) b. (i). Define what is meant by the term steam distillation? (01 mark) (ii).Explain the principle of steam distillation. (04 marks) (iii)State the requirements for a substance to be isolated by steam distillation . (01½ mark s) (iv) Name one substance apart from aminobenzene that can be isolated by steam distillation. (0½ mark) (v) State 2 advantages of steam distillation . (01 mark) c. When compound Y was steam distilled at standard atmospheric pressure, the temperature of distillation was 96 ᵒC. The vapour pressure of water at this temperature is 730 mmHg and the distillate contained 74% of water . Calculate the relative molecular mass of Y. (03 marks) d. The vapour pressure of water at 50 ᵒC is 92mmHg.A solution containing 18.1g of a non -volatile solute X in 100g of water has a 2 vapour pressure of 87mmHg at the same temperature. Calculate the relative molecular mass of X . (i) Calculate the vapour pressure of the solution . (02 marks) (ii) State and explain the effect of the concentration of the solute on the boiling point of Y. (02 marks) 3. 25cm3 of 0.1M ammonia solution wa s titrated with hydrochloric acid and the pH of the solution was measured at intervals. The table below gives the pH of the solution …