JAMB Chemistry Past Questions & Answers - Page 297

1,481.

2H2S(g) + SO2(g) → 3S(s) + 2H2O(I). The above reaction is?

a redox reaction H2S is the oxidant and SO2 is the reductant

a redox reaction in which SO2 is the oxidant and H2S is the reductant

not a redox reaction because there is no oxidant in reaction equation

not a redox because there is no reductant in the reaction equation

Correct answer is B

In the above reaction, H\(_2\)S is oxidized to H\(_2\)O while SO\(_2\) is reduced to S. Hence, H\(_2\)S is the reductant while SO\(_2\) is the oxidant.

1,482.

MnO^-₄ + 8H⁺ + ne → Mn⁺⁺ + 4H₂O. Which is the value of n in the reaction above?

View answer & explanation

Correct answer is D

MnO^-₄ + 8H⁺ + ne^- → Mn⁺⁺ + 4H₂O

Since Mn has 7 electrons on one side and 2 electrons on the other side. The value of ne^- is 5.

1,483.

Which of the following equimolar solutions, Na₂CO₃ Na₂ SO
₄CI FeCI₃ CH₃COONa,
have pH greater than 7?

FeCI ₃ and NH ₄CI

Na₂CO₃, CH₃COONa and Na,Na₂SO₄

Na₂CO₃ and CH₃COONa

FeCI₃, CH₃COONa and NH₄CI

View answer & explanation

Correct answer is C

No explanation has been provided for this answer.

1,484.

If a current of 1.5 A is passed for 4.00 hours through a molten tin salt and 13.3g of tin is deposited, what is the oxidation state of the metal in the salt?

(Sn = 118.7, F = 96500 C mol^-1)

View answer & explanation

Correct answer is B

Q = It = 1.5 x 4 x 60 x 60
13.3 g = 216000 C
118.7 g = (216000 x118.7) / (13.3) = 1927759.4 C
06500 C - 1 mole
1927759.4 C = (1927759.4) / (96500) = 1.998 = 2

1,485.

What volume of CO₂ at s.t.p would be obtained by reacting trioxocarbonate (IV) with excess acid?

(G.M.V at s.t.p = 22.4 dm³)

2.240 cm ³

22.40 cm ³

224.0 cm ³

2240 cm ³

View answer & explanation

Correct answer is B

Na₂CO₃ + 2HCC → 2NaII + H₂O
1000 cm³ IM Na₂CO₃ contains 22400 cm³
10cm³ IM Na₂CO³ will contain (10) / (100) x 224
=224 cm³
10 cm³ 0.1 Na₂CO³ will contain (o.1 x 224) / (1) = 22.4 cm³