Question

2. The titration process is used to analyze the content of some food product. Let's say you are analyzing the concentration of acetic acid in the vinegar. Answer the following question:

What would you categorize the vinegar, an acid or a base?

You have 5 mL of vinegar in a flask and 2 drops of phenolphthalein indicator. You titrate exactly 36.9 mL of
0.1 mol/L NaOH from a burette directly into the flask which gives you a pale pink color. This means the solution has reached neutralization.

Calculate n of the NaOH.

Calculate c of the vinegar in mol/L.

Depending on your answer for the previous question complete the following sentence:
                  one liter of vinegar contains …………………………. mol of acetic acid.

3. Suppose 0.22 L of 0.5 mol/L NaOH solution was titrated with 5 L of HCl using phenolphthalein indicator.

Write a balanced equation for this neutralization reaction.

Using the equation, compare the moles of NaOH with the moles of HCl at the neutralization point.

Calculate the moles of both of them.

Answer 1

2. vinegar is an acid.

no of mol of NaOH reacted = 36.9*0.1/1000 = 0.00369 mol

concentration of vinegar(C) = n/v

            = 0.00369/5*1000

            = 0.738 M

one liter of vinegar contains 0.738 mol of acetic acid

3. balanced equation: HCl(aq) + NaOH(aq) ---> NaCl(aq) + H2O(l)

                1 mol HCl = 1 mol NaOH

   no of mol of NaOH reacted = 0.22*0.5 = 0.11 mol

   no of mol of HCl taken = 0.11 mol