Question

LONG ANSWER ONLY ITS URGENT

Answer 1

Refer to the attachment for part a)

b) Magnesium ribbon on exposure to air develops a thin layer of Magnesium oxide which prevents it from reacting spontaneously. So , by rubbing the ribbon with sand paper we are actually removing that thin MgO layer for the reaction to take place as desired .

c) Zinc being more reactive than copper displaces it from its salt solution as a result of which the blue Copper sulphate becomes colourless due to the formation of Zinc sulphate. Zinc sulphate is formed from the Zinc plate leading to holes.

for all reactions refer to attachment :)