Neco Chemistry Past Questions and Answers

Question 146:

• NECO 2009

What volume of carbon (IV) oxide in dm ³ is produced at s.t.p. when 2.50g of CaCO₃ reacts with excess acid according to the following equation? CaCO₃(s) + 2HCI(aq) → CaCl₂(aq) + H₂O(1) + CO₂(g)

[CaCO₂ 100; molar volume of a gas at s.t.p. = 22.4dm ³]

A. 0.28
B. 0.56
C. 2.24
D. 5.6
E. 11.2

Question 147:

• NECO 2009

The following equations represent redox reactions EXCEPT

A. Ba²⁺(aq) + SO^2-₄ (aq) → BaSO₄(s)
B. Cl₂(g) + 2Br^- (aq) → 2CI ^- (aq) + Br₂(g)
C. Fe²⁺(aq) + ½ C I₂(aq) → Fe³⁺ (aq) + CI^-(aq)
D. 2Fe³⁺(aq) + Sn²⁺(aq) → 2Fe²⁺(aq) Sn⁴⁺ (aq)
E. Zn(s) + CU²⁺(aq) → Zn²⁺(aq) + CU(s)

Question 148:

• NECO 2009

A colourless gas with characteristics odour which dissolves in water to form an alkaline solution is ____________

A. Ammonia
B. Carbon(IV)oxide
C. Hydrogen chloride
D. Sulphur (IV) oxide
E. Sulphur (VI) oxide

Question 149:

• NECO 2009

Which of the following equations is NOT balanced?

A. CH₄(g) + 20₂(9) → CO₂(g) + 2H₂O(g)
B. CU(S) + HNO₃(aq) → Cu(NO₃)₂(aq) + 4H₂O(I) + NO(g)
C. 2KCIO₃(s) → 2KCI(s)+ 3O₂(g)
D. NaH(s) + H₂O(1) → NaOH(aq) +H₂(g)
E. Na₂SO₄(aq) + BaCl₂(aq) → BaSO₄(s) + 2NaCl(aq)

Question 150:

• NECO 2009

The process involved in the decomposition of sugar by an enzyme is called ____________

A. Dehydration
B. Esterification
C. Fermentation
D. Polymerization
E. Saponification