FRANK Solutions for Class 9 Chemistry Chapter 11 - Practical Work

Chapter 11 - Practical Work Exercise 170

Question 1

What is sublimation? Give two examples.

Solution 1

On heating certain solids they don't melt and directly get converted to their gaseous form, this process of direct conversion of solids to their gaseous form is called as sublimation. For ex: camphor and ammonium chloride undergo sublimation.

Question 2

Give atleast three parameters which should be determined to test quality of water and also give their standards available.

Solution 2

Question 3

What is decrepitation? Which salt decrepitate on heating?

Solution 3

Decrepitation is a process of breaking up of solid particles on heating, which makes a crackling sound. Lead nitrate decrepitate on heating.

Lead nitrate

Question 4

Give the colour of the following compounds:
(a) Zn(NO)₃
(b) Cu(NO₃)₂
(c) CuSO₄.5H₂O
(d) CuSO₄
(e) K₂Cr₂O₇
(f) PbS

Solution 4

(a) Zn(NO)3        = white
(b) Cu(NO3)2      = blue
(c) CuSO₄.5H₂O  = blue
(d) CuSO₄          = pale green
(e) K₂Cr₂O₇       = orange
(f) PbS               = black

Question 5

How will you distinguish between:
(a) NH₃ and Cl₂
(b) CO₂ and SO₂
(c) H₂S and SO₂
(d) H₂ and O₂

Solution 5

Question 6

Differentiate between
(a) Hard water and soft water
(b) Temporary hardness and permanent hardness
(c) Soaps and detergents

Solution 6

Question 7

(a) What chemical test you can perform in laboratory to verify that given piece of metal is zinc not copper?
(b) Give a chemical test to distinguish between Na₂S and Na₂Co₃.
(c) How will you perform a flame test for sodium?

Solution 7

Question 8

Describe the effect of heat on the following, and also write equations for each.
(a) Copper carbonate
(b) Washing soda
(c) Lead nitrate
(d) Ammonium chloride

Solution 8

Question 9

Fill in the blanks:
(a) The gas with ______ smell is hydrogen sulphide.
(b) Smell of sulphur dioxide is like that of ______.
(c) A gas with irritating odour is ______.
(d) ______ turns red litmus paper blue.
(e) The formula of lime water is ______.
(f) The ______ colour is imparted to flame by potassium.
(g) The calcium imparts ______ colour to the flame.

Solution 9

(a) Rotten egg
(b) Burning sulphur
(c) Nitrogen dioxide
(d) Alkali
(e) Ca(OH)₂
(f) Lilac
(g) Brick-red

Question 10

What do you understand by point and non point sources of water pollution?

Solution 10

Point sources of water pollution: Sources of water pollution that discharge directly into the water source are called as point sources of water pollution.
For ex: factories
Non point sources of water pollution: sources of water pollution that remain scattered and don't have specific locations for the discharge of pollutants into particular water bodies are called as non point sources of water pollution.
For ex: run off from fields.