Question

i.It is used in marketing leads of pencils.
ii.It is used as dry lubricant.
iii.It is used in marketing black paint and printer’s ink.
iv.It is used in nuclear reactors as moderator.
Which is this substance?
A.Diamond
B.Buckminsterfullerene
C.Lampblack
D.Graphite

Answer 1

We need to remember that if a chemical element is exist in different forms with the same physical state is known as allotropes. Carbon exists in many allotropic forms. Allotropes of carbon are graphite, diamond, coal, wood charcoal, lamp black, animal charcoal, gas carbon and coke. Out of these forms graphite and diamond are crystalline in nature and other elements are in amorphous form.

Complete step by step answer:
As we know that the atomic number of carbon is $6$ . Carbon is one of the most widely distributed and carbon is referred to as king of the elements due to the vast number of compounds formed with carbon, more than ten million to this date, more than any other element.
Let us see one by one,
-It is used in marketing leads of pencils.
For writing and drawing pencils are used mostly. Graphite is used in marketing leads of pencils. Graphite is a sheet-like structure that is stacked in layers, these flow against each other and it is led to flow off the pencil and if you erase the pencil letters in the paper, the graphite in the lead allows the rubber better than this does to the paper sheet.
-It is used as dry lubricant.
Graphite is used as dry lubricant ingredients, because its mineral reacts with atm water vapour. The atmospheric water vapour with that mineral creates a thin layer on the applied surface, the friction is reduced.
-It is used in marketing black paint and printer ink.
-We need to know that the lampblack is a black pigment, it is not affected by acids, light and alkalis, and lampblack is very stable. So lampblack is used as black pigments in paints and in early American house paints, lampblack was mostly used. And also it is used in inks.
-Graphite is an important additive for paint coating systems, graphite is mixed with binder in paints. Highly resistive ink is made by graphite only.
-It is used in nuclear reactors as moderator.
Graphite is a good conductor of heat and thermally stable, so it is used in nuclear reactors as moderator, graphite reacts with $C{O_2}$ and ${O_2}$ in the nuclear reactor to decrease the effectiveness.
Therefore, the graphite is the correct answer from the above information.
For (iii) It is used in marketing black paint and printers ink, (C) lampblack is also the correct option.
So, the correct answer is “Option C and D”.

Note:
We need to know that at atmospheric pressure graphite has no melting point and graphite is resistant to many chemicals. Graphite occurs naturally and is one of the most stable under standard conditions. Graphite converts into diamond under high pressure and temperature.