7
Question Question 7
What do you observe when:
(a) Blue vitriol is heated?
(b) Washing soda is exposed to air?
(c) Blue litmus solution is added to water?
(a) When blue vitriol is heated, it loses its water of crystallisation. The blue crystalline solid of copper sulphate turns into white amorphous (powder) solid and drops of colourless liquid (which is water) condense on the upper cooler parts of the test tube.
(b) When washing soda is exposed to air the white crystalline substance changes into white powder.
(c) There is no change in colour of blue litmus solution when added to water as pure water is neutral.