ignition

Question 1

intro

Answer 1

It is also called as incineration.
 It is the process by which an organic substance is strongly heated until whole of the carbonaceous
matter burns and an inorganic residue known as Ash is left behind.

OR

The process in which a synthetic compound or drug is burnt at high temperature on electric furnace to
remove organic substance (carbon) and left behind he inorganic substance and residue as ash is called
as ignition.
 This is a process of heating the organic substances in excess of air, until all the Carbon atoms have
burnt as CO2 and residue of inorganic matter (Ash) is left behind. The residue is called as Ash and the
process as Ashing.
 On laboratory scale ignition is carried out in silica or platinum crucibles.
It consists of strongly heating (“igniting”) a sample of the material at a specified temperature, allowing
volatile substances to escape, until its mass ceases to change. This may be done in air, or in some other
reactive or inert atmosphere.

Question 2

principle

Answer 2

The simple test typically consists of placing a few grams of the material in a tarred, pre-ignited crucible
and determining its mass, placing it in a temperature-controlled furnace for a set time, cooling it in a
controlled (e.g. water-free, CO2-free) atmosphere, and re determining the mass.

Question 3

explanation

Answer 3

-Ignition is a simplest type of gravimetric analysis which is used for the separation of organic and
inorganic compounds.
 In this process, weighed quantity of the solid substance is ignited in glass crucible in electric furnace.
The substance is ignited on specific temperature for definite time.
 After ignition a desiccator containing a suitable desiccant and allow to cool for 25-30 minutes and then
the contents are weighed.
 The crucible and the contents are again ignited at the same temperature for 30 minutes.
 The ignition is continued until a constant weight of inorganic ash is obtained.

Question 4

appications

Answer 4

 This process is mainly used for the standardization of organic substances and crude drugs by means of
gravimetric analysis.
 Used to determine impurities of organic salts of alkali metals such as tartarates, citrates, Benzoates and
many drugs.
 Purity of a drug is determined by its ash content.
 Zinc ointment on ignition leaves only zinc oxide.