NCERT Class – 9 Science solution: Chapter 2 Is Matter Around Us Pure-Part 11

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Question 40:

You are provided with a mixture containing sand, iron filings, ammonium chloride and sodium chloride. Describe the procedures you would use to separate these constituents from the mixture?

Answer:

  • Separate iron filings with the help of a magnet

  • Sublimation of the remaining mixture separates ammonium chloride

  • Add water to the remaining mixture, stir and filter

  • The filtrate can be evaporated to get back sodium chloride

Image of Sublimation

Image of Sublimation

Image of Sublimation

Question 41:

Arun has prepared (by mass) solution of sodium chloride in water. Which of the following correctly represents the composition of the solutions?

Answer: C

Question 42:

Calculate the mass of sodium sulphate required to prepare its (mass percent) solution in of water?

Answer:

Let the mass of sodium sulphate required be

The mass of solution would be

of solute in of solution