Q. how can you separate camphor,salt,chalk powder,sand?

The mixture can be heated and camphor will sublime that can be collected by an inverted funnel. The other three can be mixed in water and then filtered. Salt being soluble in water will dissolve in it that can be obtained by evaporation of water. Sand and chalk can be separated by sieving. Take a sieve that is bigger in pore size than any one of the two. If chalk powder is fine and sand particles are bigger, chalk powder will be filtered through and sand will remain in the sieve.