Jamb Chemistry 1988 Past Questions and Answers

Question 11:

• JAMB 1988

A mixture of starch solution and potassium iodide was placed in a test tube. On adding dilute tetraoxosulphate (lV) acid and then K₂Cr₂O₇ solutions, a blue-black colour was produced. In this reaction, the?

A. Iodide is oxidized
B. Tetraoxosulphate (Vl) acid acts as an oxidizing agent
C. Starch has been oxidized
D. K₂Cr₂O₇ is oxidized

Question 12:

• JAMB 1988

Which of the following will produce the greatest increase in the rate of the chemical reaction represented by the equation Na₂S₂O_3(aq) + 2HCl_(aq) → 2NaCI_(aq) + H₂O_(I) + SO_2(g) + S_(g)?

A. A decrease in temperature and an increase in the concentration of the reactants
B. An increase in the temperature and a decrease in the cocentration of the reactants
C. An increase in temperature and an increase in the concentration of the reactants
D. A decrease in the temperature and a decrease in the concentration of the reactants

Question 13:

• JAMB 1988

Which of the followingstatements is TRUE?

A. The dissolution of NaOH_(s) in water is endothermic
B. The heat os solution of NaOH_(s) is positive
C. The NaOH_(s) gains heat from the surroundings
D. The heat of solution of NaOH_(s) is negative

Question 14:

• JAMB 1988

Which property of a reversible reaction is affected by a catalyst?

A. Heat content (enthalphy)
B. Energy of activation
C. Free energy change
D. Equilibrium position

Question 15:

• JAMB 1988

Which of the following is used in fire extinguishers?

A. Carbon (ll) oxide
B. Carbon (lV) oxide
C. Sulphur (lV) oxide
D. Ammonia