JAMB Past Questions and Answers - Page 1181

5,901.

2-methylprop-1-ene is a structural isomer of?

A.

But-1-yne

B.

2-methyl But-1-ene

C.

3-methyl prop-1-yne

D.

But-2-ene

Correct answer is D

Isomers of Butene: are But-1-ene, But-2-ene, 2-Methylpropene or 2-methylprop-1-ene

5,902.

How many bonding pair are present in carbon(iv)oxide? 

A.

4

B.

3

C.

2

D.

1

Correct answer is A

There are 4 bond pairs in CO₂ and no lone pairs are there.

5,903.

In the extraction of iron, hot air is introduced into the blast furnace through?

A.

valves

B.

open-hearths

C.

arcs

D.

tuyeres

Correct answer is D

Pre-heated air at about 600ºC is blown into the furnaces from the bottom through the tuyeres.

5,904.

Wrought iron is obtained by heating cast iron in a furnace with?

A.

magnetite

B.

haematite

C.

carbon(ii)oxide

D.

calcium trioxosilicate(iv)

Correct answer is B

Cast iron + haematite = wrought iron

5,905.

Electrons enter into orbitals in order of increasing energy as exemplified by?

A.

1S\(^2\)2S\(^2\)2PX\(^2\)2py\(^2\)2pz\(^0\)3s\(^0\)

B.

1S\(^2\)2S\(^2\)2PX\(^2\)2py\(^1\)2pz\(^1\)3s\(^0\)

C.

1S\(^2\)2S\(^2\)2PX\(^1\)2py\(^1\)2pz\(^1\)3s\(^1\)

D.

1S\(^2\)2S\(^2\)2PX\(^2\)2py\(^2\)2pz\(^0\)3s\(^1\)

Correct answer is B

Shells and subshells are filled in energy level order, so electrons will fill the 2p subshell before the 3s shell.

And the x subshell before the y and z.