Question

Lead Pencil contains:
A.PbS
B.Graphite
C.FeS
D.Pb

Answer 1

Hint: Lead is poisonous and toxic. Graphite is carbon arranged in hexagonal ring structure and in this, the rings are connected like layers or surfaces and thus friction is created.
While FeS is black colour powdered substance made by heating grinded Iron particles with Sulphur powder.
For Pencil lead, we also need property of non-brittle nature, it should not break into particles or else it cannot be used for writing.

Complete step by step answer:

Lead is toxic and poisonous and thus could be deadly for people or students.
Thus any lead related substance cannot be used in pencil lead, but Graphite is used.
Even FeS, which is black powder cannot be used, as it is brittle. And if we use brittle substance in pencil for writing or marking then it will keep breaking and cannot be used for the purpose it is meant for.
So, in pencil lead Graphite is used for writing.
Thus, (B)Graphite is the correct answer.
Additional information: Graphite has a giant covalent structure in which: each carbon atom is joined to three other carbon atoms by covalent bonds. The carbon atoms form layers with a hexagonal arrangement of atoms.
Ancient Romans were writing in early days using a writing instrument called a stylus, which was used many years back. This precursor to the stylus pen we use on smartphones and devices was actually made out of lead. And alas, that’s why the pencil material is called lead.

Another reason we call it lead is that when graphite was discovered in Cumbria, England during the 1500s, people thought that graphite was a form of lead. Chemistry was in early days, so it was eventually determined that there was no correlation between the two.
Pencils then went on to evolve from being created by sawing graphite blocks into sticks to graphite rods being placed inside wood sleeves. Much later in 1790, it was discovered that the hardness of the graphite pencil lead could be altered by mixing graphite with clay and firing it in a kiln.

Note:
 In graphite, mix clay for sticking as a binding agent. Graphite has slippery structure with hexagonal rings arranged in Sheets manner.It occurs naturally in this form and is the most stable form of carbon under standard conditions. Under high pressures and temperatures it converts to diamond.