NECO Chemistry Past Questions & Answers - Page 9

41.

The following compounds decolorize acidified potassium tetraoxomanganate (VII) solution EXCEPT

A.

HOCH2 – CH2OH

B.

H2C –C =C– CH3

C.

H3C – HC = CH2

D.

H2C = CH2

E.

H3C – C =CH

Correct answer is A

No explanation has been provided for this answer.

42.

The percentage composition of a hydrocarbon is 79.2 carbon 20.8 hydrogen. Calculate its empirical formula [H = 1, C = 12]

A.

CH

B.

CH3

C.

CH4

D.

C2H2

E.

C2H6

Correct answer is B

Relative No of Moles for Carbon = 79.2% ÷ 12 = 6.6

Relative No of Moles for Hydrogen = 20.8% ÷ 1 = 20.8

Ratio of Moles = Carbon 6.6 ÷ 6.6 = 1                 Hydrogen = 20.8 ÷ 6.6 ~ 3

EMPIRICAL FORMULA IS      CH\(_3\)

43.

Which of the following non-metals reacts most readily with metals?

A.

Carbon

B.

Chlorine

C.

Nitrogen

D.

Phosphorus

E.

Sulphur

Correct answer is B

No explanation has been provided for this answer.

44.

Compound with the general formula CnH\(_{2n+2}\) belong to the_______ group

A.

alkanal

B.

alkane

C.

alkanoate

D.

alkene

E.

alkyne

Correct answer is B

Alkanes have the general formula of CnH2n+2 where n is the number of carbon atoms.

Alkenes have the general formula CnH2n.

The general formula for Alkynes is CnH2n-2.

45.

The process involved in the decomposition of sugar by an enzyme is called

A.

dehydration

B.

esterification

C.

fermentation

D.

polymerization

E.

saponification

Correct answer is C

No explanation has been provided for this answer.