Question

What volume of base was used 8.64ml 11.8ml 23.5ml 47.0ml 93.9ml

Answer 1

The calculated volume of the calcium hydroxide solution used in the titration is approximately 23.4 mL. Here option C is correct.

To determine the volume of the calcium hydroxide solution used in the titration, you can use the balanced chemical equation and the stoichiometry of the reaction.

The balanced equation for the reaction between potassium hydrogen phthalate (KHP) and calcium hydroxide (
`Ca(OH)_2`) is:

`\[ \text{KHP} + 2\text{Ca(OH)}_2 \rightarrow \text{Ca(KC}_8\text{H}_4\text{O}_4)_2 + 2\text{H}_2\text{O} \]`

From the equation, you can see that one mole of KHP reacts with two moles of calcium hydroxide. Therefore, the moles of
`Ca(OH)_2` can be calculated using the equation:

Moles of
`Ca(OH)_2` = Moles of KHP / 2

First, calculate the moles of KHP:

Moles of KHP = Mass of KHP / Molar mass of KHP

Moles of KHP = 6.74 g / 204.2 g/mol

Moles of KHP ≈ 0.033 mol

Now, calculate the moles of
`Ca(OH)_2`:

Moles of
`Ca(OH)_2` = Moles of KHP / 2

Moles of
`Ca(OH)_2` ≈ 0.0165 mol

Next, use the definition of molarity to find the volume of the
`Ca(OH)_2` solution:

Molarity = Moles of solute / Liters of solution

Liters of solution = Moles of solute / Molarity

Liters of solution = 0.0165 mol / 0.703 mol/L

Liters of solution ≈ 0.0234 L

Finally, convert the volume to milliliters:

Volume (mL) = 0.0234 L * 1000 mL/L

Volume (mL) ≈ 23.4 mL

Therefore, the correct answer is closest to option C - 23.5 mL.

Complete question:

6.74 g of the monoprotic acid KHP (MW2042 g/mol) is dissolved into water. The sample is titrated with a 0.703 M solution of calcium hydroxide to the equivalence point What volume of base was used?

A - 8.64 ml

B - 11.8 ml

C - 23.4 ml

D - 470 ml

E - 93.9 ml