Waec Chemistry 1994 Past Questions and Answers

Question 41:

• WAEC 1994

(a) Give one example each of a naturally occurring substance that;
(i) conforms to the general formula C(_x\)(H\(_2\)O)\(_y\);
(ii) contains the carboxyl group as its functional group.

(b) Name the process for obtaining: (i) paraffin oil from crude oil; (ii) benzene from ethyne.

Question 42:

• WAEC 1994

(a) Define oxidation in terms of electron transfer.
(b) Consider the following: Cu\(_{(s)}\) + 2Ag\(^{+}_{(Ag)}\) \(\to\) Cu\(^{2+}_{(aq)}\) + 2Ag\(_{(s)}\)
(i) State the species that is reduced
(ii) Write half-cell equation for each of the species.

Question 43:

• WAEC 1994

(a) When MgSO\(_4\).XH\(_2\)O crystals were exposed to the atmosphere for several days, three was a loss in mass
(i) What name is given to this phenomenon?
(ii) Give another example of a compound that exhibits this phenomenon
(b) If 0.50 mole of MgSO\(_4\).XH\(_2\)O has a mass of 123g. calculate the value of X. (H = 1, O = 16, Mg = 24, S = 32)

Question 44:

• WAEC 1994

(a) Write an equation to show the action of strong heat on:
(i) potassium trioxonitrate (V):
(ii) sucrose.
(b) State two observations in respect of the reaction between granulated zinc and dilute tetraoxosulphate (VI) acid.

Question 45:

• WAEC 1994

When ethane - 1,2-dioic acid is heated with concentrated tetraoxosulphate (VI) acid, a reaction represented by the following equation occurs:

(a) State the type of process involved in the reaction
(b) What is the basicity of ethane-1, s-dioic acid?
(c) List three differences in the chemical properties of the two oxides of carbon produced during the reaction