Calculate the volume of 0.300M HNO3 needed to complete neutralize 25.0ml of 0.250M Sr(OH)2

Answer 1

2HNO3 + Sr(OH)2 ==> Sr(NO3)2 + 2H2O

mols Sr(OH)2 = M x L = ?
Using the coefficients in the balanced equation, convert mols Sr(OH)2 to mols HNO3.
Then M HNO3 = mols/L. You know mols and M HNO3, solve for L (and convert to mL if needed).

Answer 2

41.6667mL