Question

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

Answer 1

Answer:

((i)Cu (s) + 2AgNO3 (aq)———–> Cu(NO3)2(aq) + 2Ag

The solution will become blue in colour and shiny silver metal will be deposited.

(ii) NaOH + HCl ———–> NaCl +  H2O+ heat

The temperature will increase because heat will be evolved.

(iii) Pb(NO3)2 (aq) + 2KI (aq)———–> Pbl2 (s) + 2KNO3 (aq)

Yellow ppt

Yellow precipitate of Pbl2will be formed.

Answer 2

Answer:

(i) copper carbonate - green to black

(ii)

(iii) sliver cholride - milky white ppt.