WAEC Chemistry Past Questions & Answers - Page 46

226.

Which of the substances is non-polar?

A.

Bromine

B.

Ammonia

C.

Water

D.

Hydrogen Bromide

Correct answer is A

 Br2 (Bromine) is nonpolar because, in this molecule, both bromine atoms have the same electronegativity due to which both atoms have equal charge distribution and results in a net-zero dipole moment.

227.

Calcium and magnesium belong to the group of the periodic table because both?

A.

are metals

B.

form cations

C.

form colourless salts

D.

have same number of valence electrons

Correct answer is D

No explanation has been provided for this answer.

228.

If 6.5g of magnesium ribbon reacts completely with Hydrochloric acid, how many grams of hydrogen gas would be liberated?

Mg(s) + 2 HCl(aq) --> MgCl 2(aq) + H 2(g)

[ H = 1.0, Mg = 24.0 ]

A.

0.54g

B.

0.70g

C.

1.08g

D.

1.40g

Correct answer is A

  24g of Mg will liberate 2g of H

: 6.5g of Mg will liberate Xg of H

= ( 6.5 X 2 ) / 24

= 0.5416g of Hygrogen ( H )

229.

The bleaching action of chlorine is through the process?

A.

Hydration

B.

Hydrolysis

C.

Reduction

D.

Oxidation

Correct answer is D

The bleaching action lof chlorinr is due to its ability to react with water to form oxochlorate(i)acid

230.

which of the following elements has the highest ionization energy?

A.

Calcium

B.

Chlorine

C.

Flourine

D.

Magnesium

Correct answer is C

The ionisation energy is the minimum energy required to remove the most loosely bound electron of an isolated gaseous atom, positive ion, or molecule.

Fluorine has the highest ionization energy when assessed through the trend on the periodic table.