Question

in the electrolysis of water name the gas collected at anode and cathode why is the volume of gas collected at one electrode double than the other what would happen if dilute H2 S o4 is not added to water

Answer 1

it is because water contains 2 molecules of hydrogen and one molecule of oxygen....
Well, the simplest answer is "electrolysis process will remain slow". 
Generally, electrolysis of water is slow. The self-ionization of water is the main reason for electrolysis. But, the conductivity of water remains low. Addition of sulfuric acid causes an increase in conductivity. Acid dissociates to produce ions which result in increased conductivity. So, if H2SO4 is not added to water, the conductivity of water will remain low resulting in slow electrolysis.

Answer 2

A.At anode is oxygen
at cathode is hydrogen

B. At cathode the volume is double because in each molecule of water there are 2 atoms of hydrogen and 1 atom of oxygen
Thus,volume of hydrogen is double that of Oxygen.

C. H2SO4 is added so the solution becomes good conductor of electricity as in acidic medium it conducts ions easily.