If 25 mL of 0.25M H2SO4 are needed to titrate 30mL of an NaOH
solution, what is the molarity of the NaOH solution?

H2SO4 is a strong acid, so for each mole of H2SO4, you get 2 moles of
H+ ions in solution.  25ml of 0.25M H2SO4 contains 0.025 liters *
0.25* (mol H2SO4)/liter * 2 (moles H+)/(mole H2SO4) = 0.0125 moles H+

In the titration, this quantity of H+ is "matched" by an equal
quantity of OH-.  That means the 30ml of the NaOH solution contains
0.0125 moles of OH-.  Because each mole of NaOH provides only one mole
of OH-, the solution also contains 0.0125 moles of NaOH.  Divide
0.0125 moles by 0.030 liters to get the molarity of the NaOH solution
(0.4166667 M).

thank you, thats what i got i just needed to be shure. you are more
then welcome to answer the question.
thanks