CBSE Class 10 Answered

1) The green colour of copper chloride fades and the solution becomes colourless.

      A red-brown coating of copper metal is deposited on the lead strip.

      Lead is more reactive than copper hence it is able to displace it from its solution.

                              Pb_(s) + CuCl_2(aq)   →  PbCl_2(aq) + Cu_(s)

2) When lead nitrate is mix with potassium iodine, a precipitation reaction occurs and yellow precipitate of lead iodide is formed.

   The equation for this reaction is

3) When the solution of potassium chloride when mixed with silver nitrate solution forms an insoluble white silver chloride.

The balance equation is 

 

                            

4) Zinc displaces copper in copper sulphate to form zinc sulphate.

               Zn_(s)   +     CuSO_4(aq)          →         ZnSO_4(aq)     +       Cu_(s)

               Zinc       Copper sulphate                 Zinc sulphate       Copper

5) Chlorine, being more electronegative than potassium displaces it from potassium bromide to form potassium chloride and bromine gas.

           Cl₂         +       2KBr          →              2KCl          +        Br₂

      Chlorine        Potassium                  Potassium        Bromine

                            bromide                      chloride    

6) Sodium hydroxide reacts with hydrochloric acid to form sodium chloride and water.

            NaOH_(aq)      +         HCl_(aq)      →      NaCl_(aq)         +        H₂O_(l)

            Sodium              Hydrochloric            Sodium                    Water

           hydroxide                 Acid                    chloride

7) Sodium sulphate reacts with barium chloride to form barium sulphate and sodium chloride solution.

                Na₂SO_{4 (aq)}   +   BaCl₂      →     BaSO_4(s)    +      2NaCl_(aq)

                Sodium            Barium                Barium              Sodium

               sulphate           chloride              sulphate             chloride