Question

A chemistry student weighs out 0.120 g of ascorbic acid into a 250. mL volumetric flask and dilutes to the mark with distilled water. He plans to titrate the acid with 0.0700 M NaOH solution. Calculate the volume of solution the student will need to add to reach the equivalence point. Be sure your answer has the correct number of significant digits.

Answer 1

9.734 mL

Step-by-step explanation:

First we calculate the moles of ascorbic acid, using its molecular weight:

• 0.120 g acid ÷ 176.12 g/mol = 6.813x10⁻⁴ mol ascorbic acid

Because NaOH and ascorbic acid react in a 1:1 ratio, we would need 6.813x10⁻⁴ moles of NaOH to titrate the acid solution.

Now we calculate the volume required of the NaOH solution:

• 6.813x10⁻⁴ mol ÷ 0.0700 M = 9.734x10⁻³ L

If we multiply by 1000 our answer becomes 9.734 mL