(i) Solid calcium oxide was taken in a container and water was added slowly to it : (a) Write the observation . (b) Write the chemical formula of the product formed (ii) What happens when carbon dioxide gas is bubbled through lime water : (a) In small amount , (b) In excess? (iii) Why do you apply paint on iron articles ?

(a) Write one equation each for decomposition reaction when energy is supplied in the form of : (i) heat , (ii) light. (b) Account for the following : (i) Paint is applied on iron articles. (ii) Oil and fat containing food items are flushed with nitrogen . (iii) When an iron nail kept in copper sulphate solution, blue colour of the solution fades and iron nail becomes brownish .

Name a metal/non-metal : (i) Which makes iron hard and strong ? (ii) Which is alloyed with any other metal to make an amalgam ? (iii) Which is used to galvanise iron articles ? (iv) Whose articles when exposed to air form a black coating ?

Why do we call our heart myogenic ?

Why do we prefer a convex mirror as a rear view mirror in vehicles?

Why do we see a rainbow in the ske only after rainfall ?

Why do we prefer a convex mirror as a rear - view mirror in vehicles ?

Why do we perfer a convex mirror as rear-view mirror in vehicle ?

Why do we prefer a convex mirror as a rear - view mirror in vehicles ?

Why do we prefer a convex mirror as a rear-view mirror in vehicles?