Chemistry Electrolysis

4OH-(aq) -->O2(g)+4e- +2H2O(l)
At anode(positively charged),colouless gas bubbles(O2) will be produced.
OH-is preferentially discharged(OH-is at higher position in electrochemical series than SO4 2-),so colourless gas bubbles(O2 )will be formed

2H+(aq) +2e- -->H2(g)
At cathode(negatively charged),colourless gas bubbles(H2)will be produced.
H+ is preferentially discharged(no other choice),so colourless gas bubbles(H2) produced.