JAMB Chemistry Past Questions & Answers - Page 339

1,692.

Water can be obtained as the only product during the?

A.

combustion of hydrocarbons

B.

neutraliization of an acid by base

C.

combustion of hydrogen

D.

electrolysis of brine

Correct answer is C

In flame of pure hydrogen burning in air, the hydrogen (H2) reacts with oxygen (O2) to form water \(H_2O\) with the release of energy. 

Hydrocarbon combustion refers to the chemical reaction where a hydrocarbon reacts with oxygen to create carbon dioxide, water, and heat.

The electrolysis of brine yields chlorine, hydrogen and sodium hydroxide.

1,693.

When sodium trioxocarbonate (IV) decahydrate loses its water of crystallization to the atmosphere, the process is?

A.

deliquescence

B.

efflorescence

C.

hygroscopic

D.

effervesecence

Correct answer is B

efflorescence, spontaneous loss of water by a hydrated salt, e.g  Sodium trioxocarbonate (IV) decahydrate \(Na_2CO_3. 10H_2O)\) also known as washing soda

1,694.

The mixture of gases used in a photographer's flash tube is?

A.

argon and krypton

B.

krypton and xenon

C.

helium and argon

D.

argon and xenon

Correct answer is B

krypton and xenon for high-speed pictures in a photographer's flash tube

1,695.

The type of bonding in \({Cu(NH_3)_4}^2\)+ is?

A.

coordinate covalent

B.

electrovalent

C.

metallic

D.

covalent

Correct answer is A

\({Cu(NH_3)_4}^2\)+: The bonding in this ion consists of coordinate covalent bonds with all bonding electrons supplied by the nitrogen atom.