NECO Chemistry Past Questions & Answers - Page 15

71.

A solution is prepared by dissolving I .96g of H2SO4 in 250 cm3 of its solution. What is the concentration in moles per dm3?

A.

0.008

B.

0.08

C.

0.1

D.

0.8

E.

8.02

Correct answer is B

No explanation has been provided for this answer.

72.

The action of zinc on an acid produces

A.

chlorine

B.

hydrogen

C.

nitrogen

D.

sulphur

E.

water vapour.

Correct answer is B

No explanation has been provided for this answer.

73.

The high boiling point of hydrogen fluoride can be explained in terms of?

A.

covalent bonds.

B.

dative bonds.

C.

dipole-dipole bonds

D.

electrovalent (ionic) bonds.

E.

hydrogen bonds.

Correct answer is E

Hydrogen fluoride is formed through covalent bonding (electron sharing) between a hydrogen atom and a fluorine atom. 

The reason is the strong electronegativity of the fluorine atom, which causes hydrogen and fluorine atoms to form hydrogen bonds in the liquid phase.

74.

What type of bond holds hydrogen fluoride molecules together when forming larger aggregate?

A.

Covalent

B.

Dative

C.

Hydrogen

D.

Ionic

E.

Metallic

Correct answer is C

No explanation has been provided for this answer.

75.

A device used in the laboratory for intermittent production of gases without heating is

A.

aspirator

B.

delivery tube

C.

fume cupboard

D.

kipp’s apparatus

E.

muller counter

Correct answer is D

No explanation has been provided for this answer.