Science - Class 9

Q89. Suggest separation technique(s) one would need to employ to separate the following mixtures.

(a) Mercury and water

(b) Potassium chloride and ammonium chloride

(c) Common salt, water and sand

(d) Kerosene oil, water and salt

 

Q90. A solution contains 40 ml of alcohol mixed with 120 ml of water. Calculate the concentration of this solution.

 

Q91. The teacher instructed three students ‘A’, ‘B’ and ‘C’ respectively to prepare a 50% (mass by volume) solution of sodium hydroxide (NaOH). ‘A’ dissolved 50 g of NaOH in 100 mL of water, ‘B’ dissolved 50 g of NaOH in 100 g of water while ‘C’ dissolved 50 g of NaOH in water to make 100 ml of solution.

Which one of them has made the desired solution and why?

 

Q92. To make a saturated solution, 36 g of sodium chloride is dissolved in 100 g of water at 293 K. Find its concentration at this temperature.

 

Q93. Differentiate between mixtures and compounds.

 

Q94. State the properties of solution.

Or

What are the properties of solution?

Or

What are the characteristics of a solution?

 

Q95. What would you observe when:

(a) a saturated solution of potassium chloride prepared at 60°C is allowed to cool to room temperature

(b) an aqueous sugar solution is heated to dryness

(c) a mixture of iron filings and sulphur powder is heated strongly?

 

Q96. How will you separate a mixture containing kerosene and petrol (difference in their boiling points is more than 25°C), which are miscible with each other?