JAMB Chemistry Past Questions & Answers - Page 428

2,136.

The gas that will form a white precipitate with acidified silver trioxonitrate (v) is

A.

NH3

B.

SO2

C.

CO2

D.

HCL

Correct answer is D

No explanation has been provided for this answer.

2,137.

Which of the following statement is true of the electrochemical series?

A.

Electropositivity of metals increase down the series

B.

Electropositivity of non-metals decrease down the series

C.

Electronegativity of non-metals decrease down the series

D.

Electropositivity of metals decreases down the series

Correct answer is D

No explanation has been provided for this answer.

2,138.

RS(aq) + HF(aq) → RF(s) + HS(aq)
ΔH = -65.7 kj mol(-1).
From the equation above, it can be deduced that

A.

the heat content of the reactants is lower than that of the products

B.

the heat content of the reactants is higher than that of the products

C.

the reaction is slow

D.

a large amount of heat is absorbed

Correct answer is B

No explanation has been provided for this answer.

2,139.

When a current I was passed through an electrolyte solution for 40 minutes, a mass X g of a univalent metal was deposited at the cathode. What mass of the metal will be deposited when a current 2I is passed through the solution for 10 minutes?

A.

X/4 g

B.

X/2 g

C.

2X g

D.

4X g

Correct answer is B

From M = zit
Where M = to the mass of the metal liberated
z = Is the electrochemical equivalent
∴ X g = 1 * 1 * 40 * 60
X g = 2400 I
Let Y represent the new mass
Y = 1*2I * 10 * 60
Y = 1200 I
Y/(X g) = 1200 I/2400 I
Y = X/2 g