Question

A 2.7912-g sample of a monoprotic acid was dissolved in water. It took 23.03 mL of a 0.2288 M NaOH to neutralize the acid. Calculate the molar mass of the acid.

Answer 1

To calculate the molar mass of the monoprotic acid, we can use the concept of stoichiometry. The balanced chemical equation for the neutralization reaction between the acid (HA) and sodium hydroxide (NaOH) is:

HA + NaOH → NaA + H2O

First, let's determine the number of moles of NaOH used in the reaction:

moles of NaOH = concentration of NaOH × volume of NaOH

moles of NaOH = 0.2288 mol/L × 0.02303 L

Next, we find the number of moles of the acid (HA) from the stoichiometric relationship:

moles of HA = moles of NaOH

Now, we can calculate the molar mass (M) of the acid using its given mass (m) and the number of moles (n):

Molar mass (M) = mass (m) / moles (n)

Molar mass (M) = 2.7912 g / moles of HA

Finally, we substitute the value of moles of HA to find the molar mass of the acid.