Quantitative Analysis This question concerns the titration of 10.0 mL of 0.0400
ID: 485818 • Letter: Q
Question
Quantitative Analysis
This question concerns the titration of 10.0 mL of 0.0400 M NaOH with 0.0200 M HCl. Neglect activity coefficients and assume 25 °C. [Note: as shown on p. 22 of the Equation Guide, we define the “fraction of titration” as the added volume of titrant divided by the equivalence volume. Thus, = 0 at the beginning of the titration and = 1 at the equivalence point.]
b. (1 pt) What volume of titrant must be added to reach the equivalence point? Calculate V.eqv using an explicit mole ratio and units and labels throughout.
Explanation / Answer
Neutralisation reaction:
NaOH (aq.) + HCl (aq.) --------------------> NaCl (aq.) + H2O (l)
Number of moles of NaOH given = 0.0400 * 10.0 / 1000. = 0.000400 mol
From the above balanced equation,
1 mol of NaOH neutralises 1 mol of HCl
So, number of moles of HCl required = 0.000400 mol
Knowing the molarity formula,
Molarity = number of moles / volume of solution in Litres
0.0200 = 0.000400 / V
V = 0.000400 / 0.0200
V = 0.0200 L
Or
V = 20.0 mL
SO, volume of HCl solution required = 20.0 mL