Write the chemical equation of the reaction with an example each in which the following change has taken place:
(i) Change in colour
(ii) Change in temperature
(iii) Formation of precipitate.

Explanation

i) Change in colour
`Cu_(g)+ 2AgNO_(3) to Cu(NO_(3))_(2(aq))+2Ag`.
The solution will become blue in colour and shining silver metal will be deposited
ii) Change in temperature.
`NaOH+HCI to NaCl+H_(2)O+"Heat"`. The temperature will increase because heat is evolved.
iii) Formation of precipitate.
`Pb(NO_(3))_(2(aq)) +2KI_(aq) to Pbl_(2)+2KNO_(3)(aq)`
Yellow PPt Yellow precipitate of `PbI_(2)` will be formed,