Chemistry questions and answers

Chemistry Questions and Answers

Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.

3,696.

MnO\(_{4(aq)}^{-1}\) + 8H\(^+ _{(aq)}\) + Y → Mn\(^{2+} _{(aq)}\) + 4H\(_2\)O\(_{(l)}\)
Y in the equation above represents

A.

2e-

B.

3e-

C.

5e-

D.

7e-

Correct answer is C

We want the number of charges on both sides of the equation to be the same. 

i.e. number of charges on the reactant side = the number of charges on the product side. 

                                                                    -1 + 8  =  2

                                                                            7 = 2

difference in number of charges = 5, hence Y = 5.

3,697.

The pOH of a solution of 0.25 mol dm-3 of hydrochloric acid is

A.

12.40

B.

13.40

C.

14.40

D.

14.60

Correct answer is B

pOH = -log [2.5 * 10-1]
= -log[-0.3979 + 1]
= 13.40

3,698.

In which order are the following salts sensitive to light?

A.

Agl > AgCl > AgBr

B.

AgCl > Agl > AgBr

C.

AgBr > AgCl > Agl

D.

AgCl > AgBr > Agl

Correct answer is C

light sensitivities of the silver halides: AgBr > AgCl > AgI. Notably; AgBr is used in production of photographic chemicals.

3,699.

HCL(aq) + H2O(l) H3O+(aq) + Cl-(aq)
In the reaction above, Cl-(aq) is the

A.

conjugate acid

B.

acid

C.

conjugate base

D.

base

Correct answer is C

No explanation has been provided for this answer.

3,700.

Hydration of ions in solution is associated with

A.

absorption of heat

B.

reduction of heat

C.

conduction of heat

D.

liberation of heat

Correct answer is D

No explanation has been provided for this answer.