JAMB Chemistry Past Questions & Answers - Page 152

756.

Calculate the quantity of electricity in coulombs required to liberate 10g of copper from a copper compound

[Cu=64, F = 96500 Cmol-1]

A.

32395.5

B.

30156.3

C.

60784.5

D.

15196.5

Correct answer is B

Cu → Cu2++ 2e
64g Cu requires 2 x 96500 coloumbs 10g Cu requires x columbs
x = 10x2x96500/64 =30156.3

757.

H 2O (g) + C (s) → H2(g) + CO(g)

The oxidizing agent in the reaction above is

A.

CO(g)

B.

C(s)

C.

H2O(g)

D.

H(2)(g)

Correct answer is C

No explanation has been provided for this answer.

758.

Zn (s) + CuSO 4(aq) → ZnSO 4(aq) + Cu (s)
In the reaction above, the oxidation number of the reducing agent changes from

A.

0 to + 4

B.

0 to + 2

C.

+ 1 to + 2

D.

+ 1 to + 3

Correct answer is B

No explanation has been provided for this answer.

759.

Which of the following salts will turn blue litmus red?

A.

Sodium tetrahydroxozincate (ll)

B.

Sodium hydrogentetraoxosulphate (VI)

C.

Sodium trioxocarbonate (lV)

D.

Zinc chloride hydroxide

Correct answer is B

No explanation has been provided for this answer.

760.

The mathematical expression of PH is

A.

log 10[OH-]

B.

log 101/[H 3 O+]

C.

log 10[H 3 O+]

D.

log 101/[OH -]

Correct answer is B

No explanation has been provided for this answer.