JAMB Chemistry Past Questions & Answers - Page 203

1,011.

Three drops of a 1.0 mol dm-3 solution of HCl was added to 20 cm3 of a solution of pH6.4. The pH of the resulting solution will be

A.

close to that of pure water

B.

less than 6.4

C.

greater than 6.4

D.

unaltered

Correct answer is B

No explanation has been provided for this answer.

1,012.

10.0 dm3 of water was added to 2.0 mol dm-3 of 2.5dm3 solution of HCl. What is the concentration of the final solution in mol dm-3?

A.

0.4

B.

8.0

C.

2.0

D.

0.5

Correct answer is A

C1V1 = C2V2

C2 = \(\frac{C_1V_1}{V_2}\)

= \(\frac{2.0 \times 2.5}{12.5}\)

= 0.4mol/dm-3

1,013.

In a water body, too much sewage leads to

A.

a decrease in the temperature of the water which cause in death of aquatic animals

B.

an increase in the number of aquatic animals in the water

C.

an increase in the bacterial population which reduces the level of oxygen in the water

D.

a decrease in the bacterial population which increases the level of oxygen in the water

Correct answer is C

No explanation has been provided for this answer.

1,014.

The solvent used for removing grease stain is

A.

turpentine

B.

ammonia solution

C.

ethanol

D.

solution of borax in water

Correct answer is B

No explanation has been provided for this answer.

1,015.

An example of a hygroscopic substance is

A.

CuO (S).

B.

MgCL2(S).

C.

CaCL2(S).

D.

NaOH(S).

Correct answer is A

No explanation has been provided for this answer.