Chemistry questions and answers

Chemistry Questions and Answers

Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.

751.

The process that occurs when two equivalent forms of a compound are in equilibrium is

A.

Isotopy

B.

Resonance

C.

Isomerism

D.

Reforming

Correct answer is B

Resonance involves two forms of a compound.
Isomerism involves two or more forms of an element.
Reforming involves the rearrangement of molecule.

This deals with a two forms of a molecule where the chemical connectivity is the same but the electrons are distributed differently around the structure.

752.

The acid anhydride that will produce weak acid in water is

A.

SO3

B.

NO2

C.

SO2

D.

CO2

Correct answer is D

H2CO3 is an example of a weak acid while H2SO4 and HNO3 are examples of a strong acid.

CO2 combines with water to give a weak trioxocarbonate (IV) acid.

CO2 + H2O → H2CO3

753.

Temporary hard water is formed when rain water containing dissolved carbon(IV) oxide flows over deposits of

A.

CaCO3

B.

Na2CO3

C.

Na2SO4

D.

CaSO4

Correct answer is A

Permanent hardness in water= Mg & Ca Sulphate.
Temporary hardness in water= Mg & Ca Carbonate.

Temporary hardness of water is caused by Magnesium and calcium hydrogencarbonate. It is formed when rainwater containing dissolved CO2 flows over deposit of CaCO3

i.e CaCO3 + CO2 + H2O → Ca(HCO3)2

754.

The tincture of iodine means iodine dissolved in

A.

ethanol

B.

bromine chloride

C.

chlorine water

D.

water

Correct answer is A

It is also called weak iodine solution. Tincture solutions are characterized by the presence of alcohol.

755.

Aluminium hydroxide is used in the dyeing industry as a

A.

dye

B.

dispersant

C.

salt

D.

mordant

Correct answer is D

Aluminium hydroxide is used in the dyeing industry as a mordant. It combines with a dye and thereby fixes it in a material.