Chemistry Past Questions and Answers

Question 31 :

• JAMB 2019

The most common type of chemical reaction which alkanes undergo is

A. Substitution
B. Addition
C. Condensation
D. Polymerisation
E. Double decomposition

Question 32 :

• JAMB 2019

Consider the following exothermic reaction

2SO_2(g) + I_2(g) 2SO_3(g)

If the temperature of the reaction is reduced from to an no other change takes place, then

A. The reaction rate increases
B. Concentration of SO₃ decreases
C. Concentration of SO₃ increases
D. SO₂gas becomes unreactive
E. I₃ gas becomes unreactive

Question 33 :

• JAMB 2019

If excess zinc is added to a bluish green solution of copper (II) sulphate, and the excess zinc filtered off after completion of reaction, a colourless solution is obtained because

A. Both zinc and copper are metals
B. The sulphate radical and the zinc ion are divalent
C. Zinc is more electropositive than copper
D. Both zinc and copper form depositive ions in solution
E. Zinc is a reducing agent

Question 34 :

• JAMB 2019

Two gas cylinders contain ethylene (ethene) and acetylene respectively. One test which can be used to distinguish between them is by

A. Passing each gas through bromine water
B. Passing each gas through dilute potassium permanganate solution
C. Passing each gas through silver nitrate solution
D. Treating each gas catalytically with excess hydrogen gas

Question 35 :

• JAMB 2019

Consider the following equation H₂O + 2Fe²⁺ + Cl₂ 2Fe³⁺ + 2Cl^- + H₂O. The only ion which behaves as an oxidising agent is

A. Fe²⁺
B. Cl₂
C. Fe³⁺
D. Cl^-
E. H₂O