Sublimation is the direct change of a solid substance into a gas without passing through the liquid state. Examples of substances that sublime include NH4Cl, I2, naphthalene, and benzoic acid. The pure solid obtained after sublimation is called the sublimate, while the original solid undergoing sublimation is the sublimand. Sublimation is carried out by slowly heating the sublimand over a sand bath under an inverted funnel that is cooled to cause the gaseous sublimate to condense on the inner side of the funnel. Sublimation is used to purify volatile thermally stable compounds and separate them from non-volatile substances.

1. SUBLIMATION

2. Define sublimation and give examples?
It is the process in which a solid is directly converted to a gas without
changing into liquid and these vapours can be condensed to form the
solid .
Examples
NH4Cl, I2, naphthalene, benzoic acid dry ice (solid CO2) etc.

3. Define sublimand and sublimate?
Sublimate: The pure solid substance obtained after sublimation is
called sublimate.
Sublimand: The substance which is being sublimed in sublimation is
called sublimand.
For example, in a mixture of NH4Cl and NaCl, NH4Cl is sublimate and
NaCl is sublimand after sublimation.

4. How the process of sublimation is carried out?
This process is done in a watch-glass covered with an inverted funnel the
substance is than slowly heated over sand bath and funnel is cooled with
wet cotton and the pure solid deposits on the inner side of the funnel .
Applicaton : For compound which are volatile and thermally stable

5. 1.Which of the following does not show sublimation?
a. NH4Cl b. benzoic acid c. naphthalene d. NaCl or K2Cr2O7
2.Direct conversion of solid into vapours is called
a. Crystallization b. sublimation c. distribution d. vaporization
3.Which of the following is purified by sublimation
a. Naphthalene b. benzoic acid c. ammonium chloride d. all of these
4.To decoulorize the crystals, we use
a. Animal charcoal b. sugar charcoal c. charcoal d. silica gel
5.Which of the following is not the drying agent?
a. CaCl2 b. Silica gel c. KOH d. Phosphorus penta oxide

6. 6.Rectified spirit is ___% ethanol and absolute alcohol is ___% ethanol.
a. 95, 100 b. 95, 99.9 c. 85, 100 d. 50, 100
7.The success of process of crystallization lies in the amount of
a. solute extracted b. solvent extracted c. crystals formed d. both a & c
8.During the process of crystallization, the hot saturated solution
a. is cooled very slowly to get large sized crystals
b. is cooled at a moderate rate to get medium sized crystals
c. is evaporated to get the crystals of the product
d. is mixed with an immiscible liquid to get the pure crystals of the
product

7. 9.Gooch crucible is made of
a. Clay b. Asbestos c. Porcelain d. Iron
10.A filtration process could be very time consuming if it were not aided
by a gentle suction which is developed:
a. if the paper covers the funnel up to its circumference
b. if the paper has got small sized pores in it
c. if the stem of funnel is large so that it dips into the filtrate
d. if the paper fits tightly