NECO Chemistry Past Questions & Answers - Page 32

156.

The atomic number of iron is 56. The number of unpaired electrons in the Fe3+ ion is

A.

1

B.

2

C.

3

D.

4

E.

5

Correct answer is E

-There are 4 unpaired electrons in Fe

-However; 5 unpaired electrons are present in Fe3+

157.

Animal charcoal differs from wood charcoal in that it

A.

has a dark colour

B.

has a high carbon content

C.

is a good absorbent

D.

is crystalline.

E.

is rich in phosphate content

Correct answer is E

Animal charcoal or bone black is the carbonaceous residue obtained by the dry distillation of bones. It contains only about 10% carbon, the remaining being calcium and magnesium phosphates (80%) and other inorganic material originally present in the bones.

158.

Which statement BEST describes the process of oxidation?

A.

addition of hydrogen

B.

loss of oxygen

C.

decrease in oxidation number

D.

loss of electrons

E.

gain of elections.

Correct answer is D

No explanation has been provided for this answer.

159.

The decreasing order of the oxidising power of the halogens is

A.

Br>I>Cl>F

B.

F>I>Cl>Br

C.

F>Cl>Br>l

D.

I>Br>Cl>F

E.

Cl>Br>F>I

Correct answer is C

No explanation has been provided for this answer.