WAEC Chemistry Past Questions & Answers - Page 252

1,256.

The gaseous product formed when ammonia is passed over heated copper (ll) oxide is

A.

oxygen

B.

nitrogen

C.

hydrogen

D.

nitrogen (l) oxide

Correct answer is B

No explanation has been provided for this answer.

1,257.

Sodium chloride is used in the following processes except in the

A.

treatment of polluted water

B.

preservation of food

C.

separation of soap from glycerol

D.

manufacture of chlorine

E.

manufacture of caustic soda

Correct answer is A

No explanation has been provided for this answer.

1,258.

Alkanols have unexpectedly high boiling points relative to their molar masses because of intermolecular

A.

hydrogen bonding

B.

metallic bonding

C.

covalent bonding

D.

ionic bonding

E.

van der Waals' forces

Correct answer is A

No explanation has been provided for this answer.

1,259.

What is the molar of hydrogen sulphide gas in the reaction H2SO4(aq) + 3H2S(g) → 4S(s) + 4H2O (l)n represented by the following equation?

A.

Reducing agent

B.

A bleaching agent

C.

A dehydrating agent

D.

A sulphonating agent

E.

An oxidizing agent

Correct answer is A

No explanation has been provided for this answer.

1,260.

Which of the following reactions is accompanied by the first ionization energy of an element X?

A.

X +(aq) → X 2+ (aq) + e-

B.

X - (g) → X(g) + e-

C.

X+ (g) → X2+ +e-

D.

X (g) → X+ (g) +e-

E.

X(s) → X + (g) + e-

Correct answer is D

 ionization energy (IE) is the minimum energy required to remove an isolated gaseous atom's most loosely bound electron. The first ionization energy is quantitatively expressed as

\(X_{(g)} + energy ⟶ X^+_{(g)} + e^−\)

where X is any atom or molecule, \(X^+\) is the resultant ion when an electron( \(e^−\)) was removed from the original atom.