We are titrating 0.1N NaOH against unknown concentration of acid, say H2SO4, using Phenolphthalein indicator. Why there's no end point appearing?

Question

It's an acid base titration experiment, where we have to find the concentration of an unown acid using known concentration of a base using indicator. Here we used 0.1 M NaOH, and 5ml H₂SO₄ made up to 100ml. On titrating we couldn't get endpoint. However we changed phenolphthalein indicator solution, crosschecked titrant. But couldn't get the end point.

Answer 1

Apparently 5 ml of H2SO4 is not enough when you add to 0.1 NaOH.  (in 100 ml of volume)

 

I'm assuming you want a pH of about 7 to be the endpoint?  You have to add enough acid to match the volume of base 0.1 N NaOH.  You know pH is related to the number of free hydrogens, right?  What was the pH of the solution at the end of your experiment?