3
Some BaSic conceptS of chemiStry
A number of classical texts, like
Atharvaveda (1000 BCE) mention some
dye stuff, the material used were turmeric,
madder, sunflower, orpiment, cochineal and
lac. Some other substances having tinting
property were kamplcica, pattanga and jatuka.
Varähmihir’s Brihat Samhita gives
references to perfumes and cosmetics.
Recipes for hair dying were made from plants,
like indigo and minerals like iron power,
black iron or steel and acidic extracts of sour
rice gruel. Gandhayukli describes recipes
for making scents, mouth perfumes, bath
powders, incense and talcum power.
Paper was known to India in the 17
th
century as account of Chinese traveller I-tsing
describes. Excavations at Taxila indicate that
ink was used in India from the fourth century.
Colours of ink were made from chalk, red lead
and minimum.
It seems that the process of fermentation
was well-known to Indians. Vedas and
Kautilya’s Arthashastra mention about
many types of liquors. Charaka Samhita also
mentions ingredients, such as barks of plants,
stem, flowers, leaves, woods, cereals, fruits
and sugarcane for making Asavas.
The concept that matter is ultimately
made of indivisible building blocks, appeared
in India a few centuries BCE as a part of
philosophical speculations. Acharya Kanda,
born in 600 BCE, originally known by the
name Kashyap, was the first proponent
of the ‘atomic theory’. He formulated the
theory of very small indivisible particles,
which he named ‘Paramãnu’ (comparable
to atoms). He authored the text Vaiseshika
Sutras. According to him, all substances are
aggregated form of smaller units called atoms
(Paramãnu), which are eternal, indestructible,
spherical, suprasensible and in motion in
the original state. He explained that this
individual entity cannot be sensed through
any human organ. Kanda added that there
are varieties of atoms that are as different as
the different classes of substances. He said
these (Paramãnu) could form pairs or triplets,
among other combinations and unseen
forces cause interaction between them. He
conceptualised this theory around 2500 years
before John Dalton (1766-1844).
Charaka Samhita is the oldest Ayurvedic
epic of India. It describes the treatment of
diseases. The concept of reduction of particle
size of metals is clearly discussed in Charaka
Samhita. Extreme reduction of particle size is
termed as nanotechnology. Charaka Samhita
describes the use of bhasma of metals in the
treatment of ailments. Now-a-days, it has
been proved that bhasmas have nanoparticles
of metals.
After the decline of alchemy, Iatrochemistry
reached a steady state, but it too declined due
to the introduction and practise of western
medicinal system in the 20
th
century. During
this period of stagnation, pharmaceutical
industry based on Ayurveda continued to
exist, but it too declined gradually. It took
about 100-150 years for Indians to learn
and adopt new techniques. During this time,
foreign products poured in. As a result,
indigenous traditional techniques gradually
declined. Modern science appeared in Indian
scene in the later part of the nineteenth
century. By the mid-nineteenth century,
European scientists started coming to India
and modern chemistry started growing.
From the above discussion, you have learnt
that chemistry deals with the composition,
structure, properties and interection of matter
and is of much use to human beings in daily
life. These aspects can be best described and
understood in terms of basic constituents of
matter that are atoms and molecules. That
is why, chemistry is also called the science of
atoms and molecules. Can we see, weigh and
perceive these entities (atoms and molecules)?
Is it possible to count the number of atoms
and molecules in a given mass of matter and
have a quantitative relationship between the
mass and the number of these particles?
We will get the answer of some of these
questions in this Unit. We will further describe
how physical properties of matter can be
quantitatively described using numerical
values with suitable units.
Unit 1.indd 3 9/9/2022 4:27:29 PM
