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Wednesday, 10 June 2026
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Chemistry Past Questions and Answers

Waec Chemistry Questions

Question 196:
(a) Give three differences between electrovalent compounds and covalent compounds
(b) List two physical properties of metals which can be accounted for by their structure
(c) Thorium (Th) metal undergoes a reaction represented by the following equation:
\(^{234}_{90}Th \to X + ^{234}_{91}Pa\)
(i) State the type of process involved in the reaction
(ii) Balance the equation equation and hence identify X.
(iii) Name one equipment which can be used to detect X.
(iv) Sketch a curveto show the mass of given quantity of thorium will change over a long period of time.
(d) Y is a moderately reactive divalent found naturally in the combined state as the trioxocarbonate (IV) salt, YCO\(_3\) is decomposed by strong heat, state the steps you would use in extracting Y from the ore. Write equation to show the chemical processes involved.
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    Question 197:
    When steam is passed over white-hot coke, the products are
    • A Carbon (IV) oxide and nitrogen
    • B Carbon (II) oxide and hydrogen
    • C Carbon (ll) oxide and nitrogen
    • D Carbon (lV) oxide and steam
    View Answer & Explanation
    Question 198:
    When steam is passed over white-hot coke, the products are
    • A Carbon (IV) oxide and nitrogen
    • B Carbon (II) oxide and hydrogen
    • C Carbon (ll) oxide and nitrogen
    • D Carbon (lV) oxide and steam
    View Answer & Explanation
    Question 199:
    The maximum number of electrons that can accommodated in the shell having the principal quantum number 3 is
    • A 3
    • B 9
    • C 10
    • D 18
    • E 32
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    Question 200:
    Methanol is obtained from wood by
    • A Esterification
    • B Bacterial decomposition
    • C Combustion
    • D Fractional distillation
    • E Destructive distillation
    View Answer & Explanation