ANSWER QUICK PLEASE If 20.0 mL of a 5.0M HCl solution are required to neutralize 10.0 mL of a NaOH
solution, calculate the molarity of the NaOH solution.

20.0 mL of 5.0 M HCl solution contains

0.0200 L * 5.0 M = 0.10 mol

of HCl.

Mixing the HCl and NaOH solutions results in

HCl + NaOH ==> NaCl + H2O

which is to say 0.10 mol of HCl reacts with 0.10 mol of NaOH. If only 10.0 mL of NaOH solution is required, then its molarity x is such that

0.0100 L * x M = 0.10 mol   =>   x = 10. M