Question

Usually potassium hydrogen phthalate is kept very pure. But Stu Dent thinks the bottle of potassium hydrogen phthalate has been accidently mixed with sodium chloride salt. He decides to use a titration to determine the amount of potassium hydrogen phthalate present. He weighs 2.3854 g of the contaminated potassium hydrogen phthalate mixture. The titration uses 17.47 mL of 0.5000 M sodium hydroxide. Use the titration volume and concentration to calculate the moles of potassium hydrogen phthalate actually reacted. Then use the molar mass (204.2 g/mol) to calculate the mass of potassium hydrogen phthalate actually reacted. Enter the mass to 4 significant digits with units of g.

Answer 1

Answer:

1.784 g

Explanation:

The equation of the reaction is;

NaOH(aq) + KHC8H4O4(aq) --------> KNaC8H4O4(aq) + H2O(l)

Number of moles of NaOH reacted = 17.47/1000 * 0.5000 M

Number of moles of NaOH reacted =8.735 * 10^-3 moles

From the reaction equation;

1 mole of NaOH reacted with 1 mole of KHC8H4O4

Hence, 8.735 * 10^-3 moles of NaOH reacts with 8.735 * 10^-3 moles of KHP.

So,

Mass of KHP reacted = 8.735 * 10^-3 moles * 204.2 g/mol = 1.784 g