Question

What is the name of the technique used to carry out the separation between each of the following?
1. Butter from Curd.
2. Salt from Sea-Water
3. Camphor from Salt

Answer 1

Hint: Think of the major differences between each of the given substances and what property could possibly be used to separate the two.
For instance, the weight of butter in comparison to curd.

Step-by-Step Solution:
Let us go through each of these cases one at a time to help you understand each individual case a bit better.
1. Butter is separated from curd by the process of Centrifugation. The principle behind this process is that the denser particles are forced to the bottom and the lighter particles stay at the top when spun rapidly.

2. Either distillation or evaporation can be used to separate salt from sea-water depending on how quickly you want the end-product, as the process of distillation is fairly faster than that of evaporation.
Distillation works as salt has a much higher boiling point than water. One way to separate salt and water at home is to boil the salt water in a pot with a lid.
Lift the lid a little so that the water that condenses on the inside of the lid and runs down the side to be collected in a separate container. Upon the complete boiling of water, the salt will remain in the pot.
Evaporation works the same way as distillation, but as mentioned above, it is marginally slower. Pour the salt water into a shallow pan. As the water evaporates, the salt will remain behind. You can speed up the process by raising the temperature or by blowing dry air over the surface of the liquid.

3. Camphor and salt can be separated using the Sublimation technique which is carried out as follows:
Heat the mixture in a crucible
Camphor being sublimable will evaporate slowly
Eventually only salt will be left.
If you want to obtain camphor as well then,
Put the mixture in a conical flask
Insert a piece of cotton or wool at the opening of the flask
Heat the mixture
The vapour of camphor is collected in the cotton piece
You can obtain the solid camphor by cooling it

NOTE: There are many different ways to separate salt from sea water. Therefore, if the way you know of isn’t one of those given above, there is no need to panic.