Question

What volume of 0.115 M M HClO 4 \rm HClO_4 solution is needed to neutralize 58.00mL mL of 8.75×10−2 M M NaOH \rm NaOH

Answer 1

Worked like the last one like this.

HClO4 + NaOH ==> NaClO4 + H2O
mols NaOH = M x L = ?
mols HClO4 = the same (see the coefficients).
M HClO4 = mols HClO4/L HClO4. You know mols and M, solve for L and convert to mL.