Question

A chemistry student weighs out of chloroacetic acid into a volumetric flask and dilutes to the mark with distilled water. He plans to titrate the acid with solution. Calculate the volume of solution the student will need to add to reach the equivalence point. Round your answer to significant digits.

Answer 1

Answer:

11.6mL of the 0.1400M NaOH solution

Explanation:

0.154g of chloroacetic acid diluted to 250mL. Titrated wit 0.1400M NaOH solution.

The reaction of chloroacetic acid, ClCH₂COOH (Molar mass: 94.5g/mol) with NaOH is:

ClCH₂COOH + NaOH → ClCH₂COO⁻ + Na⁺ + H₂O

Where 1 mole of the acid reacts per mole of the base.

That means the student will reach equivalence point when moles of chloroacetic acid = moles NaOH.

You will titrate the 0.154g of ClCH₂COOH. In moles (Using molar mass) are:

0.154g ₓ (1mol / 94.5g) = 1.63x10⁻³ moles of ClCH₂COOH

To reach equivalence point, the student must add 1.63x10⁻³ moles of NaOH. These moles comes from:

1.63x10⁻³ moles of NaOH ₓ (1L / 0.1400moles NaOH) = 0.0116L of the 0.1400M NaOH =

11.6mL of the 0.1400M NaOH solution