K.C.S.E Chemistry Q & A - MODEL 2007.PP2.QN.7

14/10/2020

KCSE Chemistry 2007 Topical Questions and Answers

All Questions Featuring Chemistry Form 1, Form 2, Form 3, Form 4, Paper 1, Paper 2 and Paper 3

The diagram below shows the set up used in an experiment to prepare chlorine gas and react it with aluminium foil. Study it and answer the question that follow

(a) In the experiment, concentrated hydrochloric acid and potassium manganate (VII) were used to prepare chlorine gas. State two precautions that should be taken in carrying out this experiment.
(b) Write the formula of another compound that could be used instead of potassium manganate (VII)
(c) Explain why it is necessary to allow the acid to drip slowly onto potassium manganate (VII) before the aluminium foil is heated.
(d) State the property of the product formed in the combustion tube that makes it possible for it to be collected in the receiver
(e) When 1.08g of aluminum foil were heated in a stream of chlorine gas, the mass of the product formed was 3.47 g
Calculate the:
(i) Maximum mass of the product formed if chlorine was in excess; (Al= 27; Cl = 35.5)
(ii) Percentage yield of the product formed
(f) Phosphorous trichloride is a liquid at room temperature. What modification should be made to set up if it is to be used to prepare phosphorous trichloride?

ANSWERS