Whenhydrogen sulphide gas is passed through a blue solution of copper sulphate, ablack precipitate of copper sulphide is obtained and the sulphuric acid soformed remains in the solution. The reaction is an example of-

(a)  a combinationreaction

(b)  a displacementreaction

(c)   a decompositionreaction

(d)  a doubledisplacement reaction

Thereaction of water and quick lime is an example of

(a)  combinationreaction

(b)  exothermicreaction

(c)   both (a) and (b)

(d)  None of these

Whenferrous sulphate is heated strongly name the gas evolved?

(a)  SO₂

(b)  SO₃

(c)   Fe₂O₃

(d)  SO₂and SO₃

Thecolour of the gas evolved on heating solid lead nitrate is

(a)  Yellow

(b)  Brown

(c)   greenish yellow

(d)  green

Astudent took solid quick lime in a china dish and added a small amount ofwater. He heard

(a)  a popping sound

(b)  a cracklingsound

(c)   a hissing sound

(d)  no sound at all