NaOH + HCl -> NaCl + H2O
Good start. Now, ignore your formula, V1*M1*n2=V2*M2*n1, please. Although you may like it, and may have been taught it, you don't seem to really understand it.
Now, working with the actual problem:
What volume of 0.10 M NaOH is needed to neutralize 30 mL of 0.20 M of the diprotic acid H2
Look and see what I've done:
1). First of all, I wrote it down, instead of taking a picture with my phone, this gives a person a chance to study a problem, to be sure they understand it.
2). I changed the units. If you don't like that or don't understand that, no problem. You can use your oid units, if you want to keep writing them.
3). They say diprotic acid, but they don't say which one. No matter, I made up a diprotic acid. I could have called it H2
(peterpanate). Notice though: they said diprotic, and you used a monoprotic acid as an example. Sorry, but your phone wasn't able to help you, whereas writing it down would. Please don't use HCl as an example again, for this problem, it just means that you won't read our help, and just want the answer given to you.
OK, lets try changing units again, to see if you have something to visualize:
You have a two stacks of 30 copper coins. You have to make stacks of coins, one silver coin, with one copper coin. How many silver coins do you need?