You're performing a titration of some acetic acid. You have reason to doubt that the grocery store is selling you vinegar at the concentration listed on the label. The label says the contents are 2.00M acetic acid. You begin performing the titration on 5mL of the acetic acid sample with 0.21M NaOH. You perform the titration and find that your indicator (phenolphthalein) turns the slightest shade of pink and determine you've added 49.4mL of the 0.21M NaOH.
What is the concentration of the acetic acid purchased from the grocery? In your answer below, please only enter a numerical value. If you enter a unit, your answer will be counted wrong. It is understood that the unit is Molar (M).