Question

A 20.00-mL sample of a weak base is titrated with 0.0568 M HCl. At the endpoint, it is found that 17.88 mL of titrant was used. What was the concentration of the weak base?

Answer 1

To find the concentration of the weak base, calculate the moles of HCl used and use the stoichiometric relationship to determine the moles of the weak base, which, when divided by the volume of the weak base in liters, gives the concentration.

Step-by-step explanation:

The concentration of the weak base can be determined using the information from the titration with HCl. The molarity of the titrant (HCl) and the volume used at the endpoint allows us to calculate the number of moles of HCl, which equals the number of moles of the weak base due to the 1:1 molar ratio in the acid-base neutralization reaction.

First, calculate the moles of HCl:

Moles of HCl = Molarity of HCl × Volume of HCl in liters

Moles of HCl = 0.0568 M × 0.01788 L

Moles of HCl = 0.00101664 mol

Since the molar ratio of acid to base is 1:1, the moles of base will be the same:

Moles of weak base = Moles of HCl

Moles of weak base = 0.00101664 mol

Finally, calculate the concentration of the weak base:

Concentration of weak base = Moles of weak base / Volume of weak base in liters

The concentration of weak base = 0.00101664 mol / 0.02000 L

Concentration of weak base = 0.050832 M

Answer 2

Answer: 0.0508mL

Explanation: Using the basic formula that states: C acid * V acid = C base * V base. we have:0.568 * 17.88 = 20 * C base.

therefore concentration of the base is 1.0156/20 = 0.0508 mL