Answer:
1.62x10⁻³ moles of NaOH were dispensed
Step-by-step explanation:
Molarity is an unit in chemistry defined as the ratio between moles of solute (In the problem, NaOH), per liter of solution.
The concentration of the solution is 0.125moles per liter. That means 1L of solution has 0.125 moles of NaOH.
The volume you dispensed in the buret was:
15.67mL - 2.73mL =
12.94mL of the 0.125M NaOH are:
12.94mL = 0.01294L * (0.125moles / L) =
1.62x10⁻³ moles of NaOH were dispensed