Jamb Chemistry 1987 Past Questions and Answers

Question 26:

• JAMB 1987

The solubility of Na₃AsO₄(H₂O)₁₂ is 38.9g per 100g H₂O. What is the mass percentage of Na₃AsO₄ in the saturated solution?
(As = 75, Na = 23, O = 16, H = 1)

A. 87.27%
B. 38.9%
C. 19.1%
D. 13.7%

Question 27:

• JAMB 1987

In which of the following are the aqueous solutions of each of the substances correctly arranged in order to decreasing acidity?

A. Ethanoic acid, milk or magnesia, sodium chloride, hydrochloric acid and sodium hydroxide
B. Ethanoic acid, hydrochloric acid, milk of magnesia, sodium chloride and sodium chloride and sodium hydroxide
C. Hydrochloride acid, ethanol acid, sodium chloride, milk of magnesia and sodium hydroxide
D. Hydrochloride acid, sodium hydroxide sodium chloride, ethanol acid, and milk of magnesia

Question 28:

• JAMB 1987

If 24.83 cm³ of 0.15 M NaOH is titrated to its end point with 39.45 cm³
of HCl, what is the molarity of the HCl?

A. 0.094 M
B. 0.150 M
C. 0.940 M
D. 1.500 M

Question 29:

• JAMB 1987

The atomic numbers of two elements X and Y are 12 and 19 respectively. The bond of these two elements is?

A. Ionic
B. Covalent
C. Neutral
D. Co-ordinate

Question 30:

• JAMB 1987

If d represents the density of a gas and K is a constant, the rate of gaseous diffusion r is related to d by the equation?

A. R = k/√d
B. R = kd
C. R =k/d
D. R = k √d