NECO Past Questions and Answers - Page 88

436.

Matter is neither created nor destroyed in the course of any chemical reactions is a statement of the law of

A.

combining volumes

B.

conservation of mass

C.

definite proportion

D.

multiple proportion

E.

reciprocal proportion.

Correct answer is B

No explanation has been provided for this answer.

437.

pH is define as

A.

[H+]

B.

–log [H]

C.

–log [H+]

D.

log [H]

E.

log [H+]

Correct answer is C

No explanation has been provided for this answer.

438.

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.

439.

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.

440.

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.