JAMB Chemistry Past Questions & Answers - Page 232

1,156.

Which of the following compounds is NOT the correct product formed when the parent metals is heated in air?

A.

Calcium oxide (CaO)

B.

Sodium oxide (Na2O)

C.

Copper (ll) oxide (CuO)

D.

Tri-iron tetroxide (Fe3O4)

E.

Aluminium oxide (Al2O3)

Correct answer is D

No explanation has been provided for this answer.

1,157.

A colourless organic compound X was burnt in excess air to give two colourless and odourless gases, Y and Z, as products. X does not decolorize blue bromine vapour, Y turns lime milky while Z gives a blue colour with copper (ll) tetraoxosulphate (IV).
Y and Z are respectively?

A.

CO2 and NH3

B.

CO and NH3

C.

SO2 and H2O

D.

CO2 and H2O

E.

SO2 and NH3

Correct answer is D

All saturated hydrocarbons are attacked by oxygen at elevated temperatures and, if oxygen is in excess, complete combustion to carbon dioxide and water occurs.

1,158.

A colourless organic compound X was burnt in excess air to give two colourless and odourless gases, Y and Z, as products. X does not decolorize blue bromine vapour, Y turns lime milky while Z gives a blue colour with copper (ll) tetraoxosulphate (IV).
Compound X is?

A.

an alkene

B.

an alkane

C.

an alkyne

D.

tetrachloromethane

E.

dichloromethane

Correct answer is B

Burning the alkane in the presence of sufficient air or oxygen; it produces carbon dioxide, water, and a huge amount of heat as a product.

If carbon dioxide is bubbled through limewater, the limewater turns milky or cloudy white.

Anhydrous CuSO4 is used to test the presence of water in any liquid because it changes its colour from white to blue in the presence of water.

1,159.

Which of the following substances is the most abundant in the universe?

A.

Carbon

B.

Air

C.

Water

D.

Oxygen

E.

Hydrogen

Correct answer is E

Element Abundance
Hydrogen 40,000
Helium 3,100
Oxygen 22
Neon 8.6
Nitrogen 6.6
Carbon 3.5
Silicon 1
Magnesium 0.91
Iron 0.6
Sulfur 0.38

1,160.

Solid sodium hydroxide on exposure to air absorbs a gas and ultimately gives another alkaline substance with the molecular formula?

A.

NaOH.H2O

B.

NaOH.N2

C.

Na2CO3O

D.

NaHCO3

E.

NaNO3O

Correct answer is C

No explanation has been provided for this answer.