Question

The direct solidification of a vapor by cooling (the reverse of sublimation) is known as-
A.Deposition
B.Sublimation
C.Liquefaction
D.Fusion
E.Vaporization

Answer 1

We generally see that a gas is first transformed into liquid then into solid or vice versa. Direct solidification means that substance in a gas phase transforms directly into a solid phase without going into liquid phase when the substance is cooled.

Complete Step-by-Step Solution:
1.Deposition-A gas when transformed directly into a solid without entering liquid phase under special conditions, then this process is called Deposition. It is the reverse of the 2.sublimation process. We generally see during winter months that water vapors directly transform into ice and stick on the windows of house and cars. It is also called de-sublimation.
3.Sublimation- In this process the solid directly into gas without entering the liquid phase. For Example- when camphor or naphthalene balls are heated they undergo sublimation and directly change to gas phase without passing through liquid phase.
4.Liquefaction- When gas is converted into liquid state under high pressure and low temperature, the process is called liquefaction of gas. This method is very useful in converting LPG gas to liquid to store in cylinders to be used in kitchens.
5.Fusion- Fusion is a process in which two elements or substances fuse together to produce a new element or substance. In chemistry, melting is called fusion because in this process the solid changes to a liquid phase when heat or pressure is provided to it.
6.Vaporization –When a liquid changes to vapour phase, the process is called vaporization. It is of two types –
a)Evaporation- which is a surface phenomenon means the molecules on surface stat vaporizing. It is the process due to which the water in the earthen pots stays cool.
b)Boiling- It is a bulk phenomenon means all the molecules in the container on the vessel go into vapour phase.

The correct answer is A.

Note: The uses of deposition are-
1.LED is coated with different substances using deposition.
2.It is used to create materials.
3.It is used to apply a thin coating to materials used for shaping and cutting purposes.
4.It can also be used to cover polymers with antimicrobial substances.