JAMB Chemistry Past Questions & Answers - Page 53

261.

Which of the following reactions is an oxidation process?

A.

2H\(^+\) + 2e\(^-\) \(\to\) H\(_2\)

B.

2O\(^{2-}\) + 4e\(^-\) \(\to\) O\(_2\)

C.

OCl\(^-\) + H\(_2\)O + 2e\(^-\) \(\to\) 2OH\(^-\) + Cl\(^-\)

D.

Cl + e\(^-\) \(\to\) Cl\(^-\)

Correct answer is B

No explanation has been provided for this answer.

262.

For the general equation of the nature
xP + yQ ⇌ mR + nS, the expression for the equilibrium constant is

A.

k[P]\(^x\)[Q]\(^y\)

B.

\(\frac{m[R][S]}{x[P]y[Q]}\)

C.

\(\frac{[P]^x[Q]^y}{[R]^m[S]^n}\)

D.

\(\frac{[R]^m[S]^n}{[P]^x[Q]^y}\)

Correct answer is D

Given:
xP + yQ ⇌ mR + nS
Let us assume they are all in aqueous solution

k = \(\frac{[R]^m[S]^n}{[P]^x[Q]^y}\)

263.

Consider the reaction
A\(_{(s)}\) + 2B\(_{(g)}\) → 2C\(_{(aq)}\) + D\(_{(g)}\)
What will be the effect of a decrease in pressure on the reaction?

A.

the equilibrium will shift

B.

rate of forward reaction will increase

C.

rate of backward reaction will increase

D.

rates of forward and backward reaction are not affected

Correct answer is C

Given: The equation below
A\(_{(s)}\) + 2B\(_{(g)}\) → 2C\(_{(aq)}\) + D\(_{(g)}\)

According to Le Chatelier's Principle:

Pressure changes affects only the gaseous reactants and products
There must be different amount of gaseous particles on both sides.

Generally; a decrease in the pressure shifts the equilibrium position in favor of the side with larger volume of gases.

I.e  rates of backward reaction.

264.

Which of the following represents the kind of bonding present in ammonium chloride?

A.

ionic only

B.

covalent only

C.

ionic and covalent

D.

dative covalent

Correct answer is C

No explanation has been provided for this answer.

265.

When ammonia and hydrogen ion bond together to form ammonium ion, the bond formed is called

A.

electrovalent bond

B.

compound bond

C.

ionic bond

D.

covalent bond

Correct answer is D

When ammonia and hydrogen ion go into bonding, they form ammonium ion with a one dative covalent bond and three covalent bonds.