Question

What volume of a 3.5 M HCl is required to completely neutralize 50.0 ml of a 2.0 M NaOH?

Answer 1

by M u mean concentration?

Answer 2

if so then
first u need to write balanced equation
NaOH + HCl -> NaCl + H2O
for NaOH we know volume and concentration so we use formula
concentration = mole/ volume
we need to find mole, thus we make it as subject
mole = concentration*volume
mole = 2.0*50 = 100moles of NaOH reacted with HCl
from equation you can see that the ratio between NaOH and HCl is 1:1
thus mole of HCl is also 100 mole
so for HCl we already know concentration and now mole also
we again use concentration = mole/volume formula
this time we'll make volume as subject so
volume = mole/concentration
volume = 100 / 3.5 = 28.57 ml
i hope u get the working and next time you can do it on your own :)