how many milliliters of a 2.61 m h2so4 solution are needed to neutralize 71.50 ml of a 0.855 m koh solution

Answer 1

Apparently you don't know where the caps key is. You should find it because 2.61 m and 2.61M don't meant the same thing. I will assume that is 2.61 M and 0.855 M.
2KOH + H2SO4 ==> K2SO4 + 2H2O

mols KOH = M x L = ?
mols H2SO4 = 1/2 mols KOH. Look at the coefficients in the balanced equation.
Then M H2SO4 = mols H2SO4/L H2SO4. You know mols and M, solve for L and convert to mL.