Jamb Chemistry 1978 Past Questions and Answers

Question 6:

• JAMB 1978

A small quantity of solid ammonium chloride (NH₄Cl) was heated gently in a test tube, the solid gradually disappears to produce two gases. Later, a white cloudy deposit was observed on the cooler part of the test tube. The ammonium chloride is said to have undergone

A. Distillation
B. Sublimation
C. Precipitation
D. Evaporation
E. Decomposition

Question 7:

• JAMB 1978

Elements P, Q, R, S have 6, 11, 15, 17 electrons respectively, therefore,

A. P will form an electrovalent bond with R
B. Q will form a covalent bond with S
C. R will form an electrovalent bond with S
D. Q will form an electrovalent bond with S
E. Q will form a covalent bond with R

Question 8:

• JAMB 1978

An element X forms the following compounds with chlorine; XCl₄, XCl₃, XCl₂. This illustrates the

A. Law of multiple proportions
B. Law of chemical proportions
C. Law of simple proportions
D. Law of conservation of mass
E. Law of definite proportions

Question 9:

• JAMB 1978

The oxidation state of chlorine in potassium chlorate is

A. +1
B. +2
C. +3
D. +5
E. +7

Question 10:

• JAMB 1978

When air which contains the gases Oxygen, nitrogen, carbondioxide, water vapour and the rare gases, is passed through alkaline pyrogallol and then over quicklime, the only gases left are;

A. Nitrogen and carbondioxide
B. The rare gases
C. Nitrogen and oxygen
D. Nitrogen and the rare gases
E. Nitrogen, carbondioxide and the rare gases