Jamb Chemistry 1984 Past Questions and Answers

Question 36:

• JAMB 1984

A piece of sea shell, when dropped into a dilute solution of hydrochloric acid, produces a colourless, odourless gas which turns clear limewater milky. The sea shell contains

A. Sodium chloride
B. Ammonium nitrate
C. Calcium carbonate
D. Calcium chloride
E. Magnesium chloride

Question 37:

• JAMB 1984

Which of the following electrodes is used in electrolysis of bauxite (Al₂O₃) in molten cryolite?

A. Steel electrodes
B. Carbon electrodes
C. Mercury electrodes
D. Carbon anode and steel cathode
E. Carbon cathode and stell anode

Question 38:

• JAMB 1984

An aqueous solution of a metal salt, M, gives a white precipitate with NaOH which dissolves in excess NaOH. With aqueous ammonia, the solution of M also gives a white precipitate which dissolves in excess ammonia. Therefore cartion in M is

A. Zn ⁺⁺
B. Ca⁺⁺
C. Ai⁺⁺⁺
D. Pb⁺⁺
E. Cu⁺⁺

Question 39:

• JAMB 1984

At S. T. P how many litres of hydrogen can be obtained from the reaction of 500 cm³ of 0.5 M H ₂SO ₄ with excess zinc metal?
(Gram molecular volume of H₂ = 22. 4 dm ³)

A. 22.4 dm ³
B. 11 . 2 dm ³
C. 6. 5 dm ³
D. 5. 6 dm ³
E. 0. 00 dm ³

Question 40:

• JAMB 1984

The solubility curves of four substances are shown in the figure above. Which of the four substances would crystallize from a saturated solution cooled from 353K(80^oC)to 323K(50[sup][/sup]C)?

A. P and Q
B. P and R
C. P and S
D. R and S
E. Q and R