NaOH (aq) + HCl(aq) H2O + NaCl (aq)
If 25.0 mL of a 0.2 M NaOH solution is used for the reaction
shown above, how many moles of NaOH were involved in the
reaction? _moles.

The answer to your question is 0.005

Explanation:

Data

Volume of NaOH = 25 ml

[NaOH] = 0.2 M

moles of NaOH = ?

To solve this problem is not necessary to have the chemical reaction. Just use the formula of Molarity and solve it for moles.

Formula

Molarity = moles / volume

-Solve for moles

moles = Molarity x volume

-Convert volume to liters

          1000 ml 1 l

              25 ml x

               x = (25 x 1) / 1000

               x = 0.025 l

-Substitution

moles = 0.2 x 0.025

-Result

moles = 0.005