Year : 
2009
Title : 
Chemistry
Exam : 
JAMB Exam

Paper 1 | Objectives

11 - 20 of 50 Questions

# Question Ans
11.

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

Detailed Solution

krypton and xenon for high-speed pictures in a photographer's flash tube
There is an explanation video available below.
12.

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

A. deliquescence

B. efflorescence

C. hygroscopic

D. effervesecence

Detailed Solution

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
There is an explanation video available below.
13.

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

Detailed Solution

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.
There is an explanation video available below.
14.

If 10.5g of lead (II) trioxonitrate (V) is dissolved in 20cm3 of distilled water at 18oC, the solubility of the solute in mol dm-3 is
[Pb = 207, N = 14, O = 16]

A. 1.60

B. 5.25

C. 16.00

D. 525.00

Detailed Solution

There is an explanation video available below.
15.

For a given solute, the concentration of its saturated solution in different solvents are

A. the same at the same temperature

B. different at the same temperature

C. the same at different temperature

D. constant

Detailed Solution

There is an explanation video available below.
16.

The major source of oxides of nitrogen is from the burning of

A. coal

B. wood

C. fuel

D. chlrofluorocarbons

Detailed Solution

There is an explanation video available below.
17.

The acid used in electrolysis of water is dilute?

A. HNO3

B. CH3COOH

C. H2SO4

D. HCl

Detailed Solution

The electrolyte is dilute sulfuric acid (= acidified water) which, during electrolysis is split into hydrogen and oxygen gases.
There is an explanation video available below.
18.

What volume of 1.5M solution of KOH would contain 0.045 moles

A. 67.50 cm3

B. 30.00 cm3

C. 6.75 cm3

D. 3.00 cm3

Detailed Solution

There is an explanation video available below.
19.

The salt formed from a reaction between citric acid and sodium hydroxide in solution will be?

A. acidic

B. basic

C. complex

D. neutral

Detailed Solution

Citric acid has 3 carboxyl groups, therefore, when reacts with NaOH, there is a simple salification reaction that will produce the trisodium citrate / sodium citrate.
Trisodium citrate is a tribasic salt of citric acid. It is produced by complete neutralization of citric acid with high purity sodium hydroxide or carbonate and subsequent crystallization and dehydration.
There is an explanation video available below.
20.

The colour changes observed when testing for reducing agents using acidified potassium heptaoxodichromate (VI) solution is?

A. yellow to purple

B. orange to green

C. green to orange

D. purple to yellow

Detailed Solution

Reducing agent like SO\(_2\).
Sulphur dioxide gas (SO\(_2\)) is bubbled through acidified potassium dichromate. The orange solution turns green.
There is an explanation video available below.
11.

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

Detailed Solution

krypton and xenon for high-speed pictures in a photographer's flash tube
There is an explanation video available below.
12.

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

A. deliquescence

B. efflorescence

C. hygroscopic

D. effervesecence

Detailed Solution

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
There is an explanation video available below.
13.

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

Detailed Solution

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.
There is an explanation video available below.
14.

If 10.5g of lead (II) trioxonitrate (V) is dissolved in 20cm3 of distilled water at 18oC, the solubility of the solute in mol dm-3 is
[Pb = 207, N = 14, O = 16]

A. 1.60

B. 5.25

C. 16.00

D. 525.00

Detailed Solution

There is an explanation video available below.
15.

For a given solute, the concentration of its saturated solution in different solvents are

A. the same at the same temperature

B. different at the same temperature

C. the same at different temperature

D. constant

Detailed Solution

There is an explanation video available below.
16.

The major source of oxides of nitrogen is from the burning of

A. coal

B. wood

C. fuel

D. chlrofluorocarbons

Detailed Solution

There is an explanation video available below.
17.

The acid used in electrolysis of water is dilute?

A. HNO3

B. CH3COOH

C. H2SO4

D. HCl

Detailed Solution

The electrolyte is dilute sulfuric acid (= acidified water) which, during electrolysis is split into hydrogen and oxygen gases.
There is an explanation video available below.
18.

What volume of 1.5M solution of KOH would contain 0.045 moles

A. 67.50 cm3

B. 30.00 cm3

C. 6.75 cm3

D. 3.00 cm3

Detailed Solution

There is an explanation video available below.
19.

The salt formed from a reaction between citric acid and sodium hydroxide in solution will be?

A. acidic

B. basic

C. complex

D. neutral

Detailed Solution

Citric acid has 3 carboxyl groups, therefore, when reacts with NaOH, there is a simple salification reaction that will produce the trisodium citrate / sodium citrate.
Trisodium citrate is a tribasic salt of citric acid. It is produced by complete neutralization of citric acid with high purity sodium hydroxide or carbonate and subsequent crystallization and dehydration.
There is an explanation video available below.
20.

The colour changes observed when testing for reducing agents using acidified potassium heptaoxodichromate (VI) solution is?

A. yellow to purple

B. orange to green

C. green to orange

D. purple to yellow

Detailed Solution

Reducing agent like SO\(_2\).
Sulphur dioxide gas (SO\(_2\)) is bubbled through acidified potassium dichromate. The orange solution turns green.
There is an explanation video available below.