WAEC Past Questions and Answers - Page 1675

8,371.

If the recommended spacing for a tree crop is 2.5cm by 4.0m.determine the number of seedlings required to plant a 2 hectare farmland.

A.

1,000

B.

2,000

C.

10,000

D.

20,000

Correct answer is B

No explanation has been provided for this answer.

8,372.

Crop rotation decreases the incidence of pests by

A.

Breaking life cycles of pests

B.

Attracting pest predators

C.

Sterilizing the soil

D.

Maintaining soil fertility

Correct answer is A

No explanation has been provided for this answer.

8,373.

Which of the following is the relative molecular mass of a compound which has empirical formula CH\(_2\)O? (H = 1; C = 12; O = 16)

A.

42

B.

45

C.

126

D.

180

E.

145

Correct answer is D

Empirical formula = CH\(_2\)O

= 12 + (2 x 1) + 16

= 30

Molecular formula = (CH\(_2\)O)\(_n\), where n is a whole number.

= 30n

\(\therefore\) From the options, only 180 is a multiple of 30. Hence, that is the only likely molecular mass with respect to CH\(_2\)O.

8,374.

The process of grafting in crop production involves

A.

The fusion of gametes of two crops

B.

Indicating rooting from stems

C.

The transfer of a bud from one crop to another

D.

The joining of two parts from related crops

Correct answer is D

No explanation has been provided for this answer.

8,375.

The reaction between alkanoic acids and alkanols in the presence of a mineral acid is known as

A.

saponification

B.

hydrolysis

C.

polymerization

D.

esterification

E.

dehydration

Correct answer is D

No explanation has been provided for this answer.