A8.20 g sample of an aqueous solution of perchloric acid contains an unknown amount of the acid. if 20.4 ml of 0.922 m potassium hydroxide are required to neutralize the perchloric acid, what is the percent by mass of perchloric acid in the mixture?

The percent by mass of perchloric acid in the mixture is 22.92 %.

Explanation:

We are given:

Volume of potassium hydroxide = 20.4mL = 0.0204 L   (Conversion factor: 1 L = 1000 mL)

Molarity of the solution = 0.922 moles/ L

Putting values in above equation, we get:

By Stoichiometry of the reaction:

1 mole of potassium hydroxide reacts with 1 mole of perchloric acid.

So, 0.0188 moles of potassium hydroxide will react with = of perchloric acid.

Moles of perchloric acid = 0.0188 moles

Molar mass of perchloric acid = 100.46 g/mol

Putting values in above equation, we get:

We are given:

Mass of perchloric acid = 1.88 g

Mass of solution = 8.20 g

Putting values in above equation, we get:

Hence, the percent by mass of perchloric acid in the mixture is 22.92 %.

vanderwaal's forces of attraction are the electrostatic intermolecular forces that exist in a molecule due to the temporary or permanent dipoles that are developed in a molecule. in , the major intermolecular forces are dipole-dipole interactions as the molecule is polar (bent structure). so the vanderwaal's forces of interaction in between molecules are the permanent dipole-dipole interactions that develop due to the dipole that exists in between the polar h - s bond. the positively charged hydrogen atom is attracted towards the negative end of the dipole that is sulfur of the adjacent molecule. therefore, these forces of attraction are relatively stronger than that of london dispersion forces that exist in non polar molecules.