BPSC PGT Chemistry: p-Block Elements – Allotropes of Carbon

1. Which of the following is the chemical formula of fullerenes?

a) C0

b) C6

c) C

d) C60

Answer: d
Explanation: Fullerene represents a crystalline allotrope of carbon and the only pure form of carbon. A C60 molecule forms fullerene, and scientists use it in microscopic ball bearings, lightweight batteries, and in the synthesis of new plastics and drugs.

2. Which of the following is known as the Black lead?

a) Charcoal

b) Diamond

c) Graphite

d) Fullerenes

Answer: c

Explanation: Graphite is also a crystalline form of allotropic carbon, which is dark grey in color, it has hexagonal plates, the hybridization of carbon is sp2 and it is a good conductor of heat and electricity due to the presence of electrons. People know it as black lead, and they also use it as a very good lubricant.

3. Carbon black is the same as coke.

a) False

b) True

Answer: a

Explanation: Manufacturers produce coke by destructively distilling coal, while they form carbon black by burning natural gas in a limited supply of air. They then mix carbon black with rubber to make automobile tires. Though both represent amorphous allotropes of carbon, they remain different substances.

4. Wood Charcoal is an allotrope of _____________

a) carbon

b) silicon

c) nitrogen

d) germanium

Answer: a

Explanation: We obtain wood charcoal by heating wood strongly in the absence of air. When we heat it with steam, it becomes more activated, and we use it to remove coloring matter and foul-smelling gases. It represents an amorphous allotrope of carbon.

5. Bituminous is a common type of _____________

a) calcium

b) borax

c) coal

d) Coke

Answer: c

Explanation: The different types of coal are

Peat 60% of carbon,
lignite 70% of carbon,
Bituminous 78% of carbon,
semi-bituminous 83% of carbon and
anthracite 90% of carbon. Among them,
Bituminous is the most common variety of coal.

6. What do we call the suspension of graphite in water?

a) Gaseous bag

b) Aqua Dag

c) Oil Dag

d) Liquid Dag

Answer: b

Explanation: Graphite is a crystalline allotrope of carbon. When graphite is mixed in water, it forms Aquadag, and when mixed in oil, it forms Oildag. People commonly use aquadag as a coating in cathode ray tubes.

7. Half many five-membered rings are there in fullerenes?

a) 34

b) 15

c) 12

d) 10

Answer: c

Explanation: Fullerenes (C₆₀) are made up of 12 five-membered rings and 20 six-membered rings.Each five-membered ring joins with six-membered rings; furthermore, the six-membered rings connect with both five- and six-membered rings.

8. Wood Charcoal is an allotrope of _____________

a) carbon

b) silicon

c) nitrogen

d) germanium

Answer: a

Explanation: Manufacturers make wood charcoal by heating wood strongly without air. Therefore, when they treat it with steam, it becomes activated, and they use it to remove colors and unpleasant gases. It represents an amorphous allotrope of carbon.

9. Which of the following is an amorphous allotrope of carbon?

a) Diamond

b) Fullerenes

c) Graphite

d) Lampblack

Answer: d
Explanation: Diamond, graphite, and fullerenes are crystalline allotropes of carbon, while lampblack is an amorphous form. Manufacturers make lampblack by burning vegetable oils with limited air, and they use it to make printing ink, black paint, varnish, and carbon paper.

10. Manufacturers use bone black to manufacture pyridine.

a) True

b) False

Answer: a

Explanation: We get bone black (animal charcoal) by heating bones in an iron retort (destructive distillation). Moreover, this process also gives bone oil and pyridine. We use bone black as an adsorbent. On burning, it forms bone ash (calcium phosphate), which industries use to make phosphorus and phosphoric acid.