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.

1.

Reduction of nitroalkanes, nitrites and amides is a route for the preparation of

A.

amines

B.

alkenes

C.

polymers

D.

detergents

Correct answer is A

Reduction of nitroalkanes, nitrites and amides is a route for the preparation of amines

2.

A red precipitate of copper (I) carbide is formed when ammonium solution of copper (I) chloride is introduced into

A.

CH2 = CH - CH2 - CH3

B.

CH3 CH2 - C ≡ CH

C.

CH3 CH2 CH2 CH3

D.

CH3 - C C - CH3

Correct answer is B

Terminal alkynes react with ammoniacal copper(I)chloride to produce a red precipitate.

3.

A hydrocarbon X with a molar mass of 26 consists of 92.3% carbon. What is its molecular formular?

A.

C2H2

B.

C3H3

C.

C4H4

D.

C5H5

Correct answer is A

% of H2 = 100 - 92.3 = 7.7%
mole = Carbon [92.3 / 12] = 7.7

            Hydrogen [7.7 / 1] = 7.7

divide with the lowest:


Carbon - 7.1 / 7.1 = 1

Hydrogen  - 7.1 / 7.1 = 1


empirical formula = CH


(CH)n = 26
(12 + 1)n = 26
(13)n = 26
n = 26/13 = 2


molecular formula = C\(_2\)H\(_2\)

4.

The IUPAC nomenclature for the structure above is

A.

2, 3 - dichloro - 4, 4, 5 - trimethyl pent - 2 - ene

B.

4, 5 - dichloro - 2, 3 - dimethyl hex - 2 - ene

C.

2, 3 - dichloro - 4, 4 - dimethyl hex - 2- ene

D.

2, 3 dichloro - 2, 2 - dimethyl hex - 2 - ene

Correct answer is C

The longest carbon chain in the compound is the hex-2-ene.

Counting all the attachments, the IUPAC nomenclature of the compound is 2,3 - dichloro-4,4- dimethyl hex-2-ene.

5.

If glucose is heated with concentration tetraoxosulphate (VI) acid, it will be dehydrated to

A.

carbon

B.

carbon (IV) oxide

C.

ethene

D.

ethanol

Correct answer is A

If glucose is heated with concentrated tetraoxosulphate(VI)acid, it will be dehydrated to carbon.

6.

If the silver mirror test is positive, it indicates the presence of an

A.

alkyne

B.

alkanol

C.

alkanone

D.

alkanal

Correct answer is D

Alkanals give a positive result for the silver mirror test(Tollen's reagent).

7.

The type of isomerism shown by cis- and trans- isomers is

A.

optical isomerism

B.

positional isomerism

C.

functional isomerism

D.

geometrical isomerism

Correct answer is D

The type of isomerism shown by the cis- and trans- isomers is geometrical isomerism

8.

The most common ores of iron include

A.

haematite, malachite and limonite

B.

chalcocite, calamine and bornite

C.

magnetite, haematite and limonite

D.

magnetite, chalcocite and bornite

Correct answer is C

The most common ores of iron are magnetic, haematite and limonite

9.

which of the following gives a precipitate when treated with NaOH solution?

A.

AlCl3

B.

NH4Cl

C.

Na2CO3

D.

CH3COONa

Correct answer is A

Sodium hydroxide reacts with aluminium chloride to form a precipitate; aluminium hydroxide ; AlCl3 (Alumunium chloride).

10.

Leads is used for making bullets and lead shots because of its

A.

resistance to corrosion

B.

low melting point

C.

high density

D.

flexibility

Correct answer is C

Lead is used for making bullets and lead shots because of its high density.