How many ml of 0.10 m naoh should the student add to 20 ml?

I'm not sure exactly what you're asking here, but I'll give it a shot.

If you take 20 mL of .10 M NaOH, solve for how many moles you have

20 mL / 1000 mL x .10 M NaOH = .002 moles NaOH

Hno3(aq) → h+(aq) + no3−(aq). picture ii best represents the strong acid hno3. strong acids are strong electrolytes