(a)(i) Give two differences between a conductor and an electrolyte.

(ii) State three applications of electrolysis.

(iii) Write equation for the reaction at each electrode when a dilute solution of sodium chloride is electrolysed using carbon electrodes.

(b)(i) What is an electrochemical cell?

(ii) Give two examples of primary cells.

(iii) Split the following equation into two balanced hall cell equations. Mte + Fe\(^{2+} \to Mg^{2+} + Fe\).

(c)(i) A current of 0.72 amperes was passed through dilute tetraoxosulphate (VI) acid for 3 hours 20 minutes. Calculate the quantity of electricity that was passed

(ii) If 1 dm\(^3\) of gas evolved at the cathode during the electrolysis of acidified water, what was the volume of gas evolved at the anode?

(d)(i) 20g of copper(II) oxide was warmed with 0.05 mole of tetraoxosulphate (VI) acid. Calculate the mass of copper (II) oxide that was in excess. The equation for the reaction: CuO\(_{(s)}\) + H\(_2\)SO\(_{4(aq)}\) ---> CuSO\(_{4(aq)}\) + H\(_2\)O\(_l\) [0 = 16 ; Cu = 64]

(ii) What type of reaction was involved in (d)(i)?

(a)(i) Define allotropy.

(ii) Name the allotrope of carbon used in gas masks.

(iii) Mention two other elements which exhibit allotropy apart from carbon.

(b) List the products of each of the following reactions:

(i) Heating coal in the absence of air.

(ii) Burning of candle wax in plentiful supply of air

(c)(i) State the two properties of carbon (IV) oxide which make it useful in extinguishing fire.

(ii) Write an equation for the reaction of carbon (IV) oxide with lime water

(iii) Calculate the volume of oxygen that was in excess if 150cm\(^3\) of carbon (II) oxide was burnt in 80cm\(^3\) of oxygen according to the following equation: 2CO\(_{(g)}\) + O\(_{2(g)}\) \(\to\) 2CO\(_{2(g)}\).

(d)(i) State how nitrogen can be obtained from ammonia gas.

(ii) Name the gaseous fuels obtained when steam and air are passed over red hot coke.

(iii) Which of the fuels in (d)(ii) has the lower heating ability? Give reason for your answer.

(a)(i) List two elements which react with steam at red heat to produce hydrogen.

(ii) Explain why an aqueous solution of potassium bromide turned reddish brown on bubbling chlorine through it.

(iii) Write an equation for the reaction in (a)(ii).

(b)(i) Name two types of chemical industry that use limestone as raw material.

(ii) Give one example of hygroscopic substances.

(iii) Copy and complete the table below.

(c) In the contact process for the manufacture of tetraoxosulphate (VI) acid;

(i) State how sulphur (IV) oxide is obtained;

(ii) Write an equation for the reaction that takes place in the catalyst chamber;

(iii) Give the steps required to convert sulphur (VI) oxide to acid.

(d)(i) List two disadvantages of hard water.

(ii) Mention three methods which can be used to remove both permanent and temporary hardness in water at the same time.

(iii) State the role of alum and chlorine respectively in the purification of water for town supply.

(a) List two gases in each case which;

(i) can be used to demonstrate the fountain experiment;

(ii) decolourize acidified potassium tetraoxomanganate (VII).

(b) State briefly how you would distinguish between

(i) crystals of PbCO\(_3\) and Pb(NO\(_3\)) using heat;

(ii) solutions of NH\(_4\)CI and NaCl using litmus paper.

(c) Mention two changes that would be observed on adding moderately concentrated hydrochloric acid to iron filings

Credit will be given for strict adherence to instructions, for observations precisely recorded and for accurate inferences. All tests observations and inferences must be clearly entered in your answer book. in ink, at the time they are made.

C is a mixture of two inorganic compounds. Carry out the following exercises on C. Record your observations and identify any gases evolved. State the conclusion you draw from the result of each test.

(a) put all of C into a beaker and add about 10cm\(^3\) of distilled water. Stir thoroughly and filter. Keep both the residue and the filtrate

(b) Divide the filtrate into three portions.

(i) To the first portion, add sodium hydroxide solution in drops until ít is in excess. 

(ii) To the second portion, add aqueous ammonia in drops until it is in excess.

(iii) To the third portion, add about 2cm\(^3\) of barium chloride solution, followed dilute hydrochloric acid in excess.

(c) Put the residue in a test tube and add about 2cm\(^3\) of dilute tetraoxosulphate (VI) acid. Shake the mixture and warm.

(i) Add aqueous ammonia in drops to the mixture from (c) (i) above until it is in excess.