JAMB Chemistry Past Questions & Answers - Page 105

521.

The oxidation state of sulphur on H2SO4 acid is

A.

-4

B.

+6

C.

4

D.

-8

Correct answer is B

In SO4. The state of oxygen oxidation number is -2. Options A,C,D do not belong to the oxidation state in SO4

522.

S block elements of the periodic table one made up of

A.

groups 1, 2, 3

B.

groups 1, and 2

C.

group 3

D.

group 3 to 7

Correct answer is B

S block elements only are made up of group 1 and 2 options A,C,D takes place of the other blocks in the periodic table p,d,f etc.

523.

In the electrolysis of CuSo4(g) using platinum electrode the reaction at the anode is

A.

4H+ 4e - 2H2

B.

4OH= 4e- + 2H2O + O2

C.

2OH - 2e- = 2OH

D.

2OH- + 2OH = 2H2O + O2

Correct answer is B

40H − 4e → 2H2O + O2is the reaction of sun at the anode in the electrolysis of CuSO4 (g) using platinum particles. Option A,C,D are not formed as a result of the equation

524.

The principal constituent of natural gas is

A.

methane

B.

ethane

C.

propane

D.

Butane

Correct answer is A

Methane CH4.A. is the principal and commercial constituent natural gas. Option B,C,D are also constituent of natural gas but they are not commercial and of economic importance

525.

Chlorine consisting of two isotope of mass number 35 and 37 in the ratio 3:1 has an atomic mass of 35.5. Calculate the relative abundance of the isotope of mass number 37

A.

20

B.

25

C.

60

D.

75

Correct answer is B

Let the relative abundance of the energy with mass 37 be
Total relative abundance of the isotope of mass 359100-k)
Total mass of isotope of mass 37-37x, while that of 35-359(100x)
-37x + 3500 − 35 − 35.5
-37x + 3500 − 35n − 35.5
Mean mass of chlorine atom − (2n + 3500)/ ÷ 100
= 35.5
2x + 3500 − 3550yx = 50/2