Question

Acid H2X gives two H ions. A 1.50 g sample of H2X reacts completely with 35.0 ml of 0.400 M NaOH solution. What is the molar mass of H2X?

Answer 1

To find the molar mass of H2X, we calculated the moles of NaOH used, found the moles of H2X, and divided the mass of the H2X sample by the number of moles. The molar mass of H2X is determined to be 214.29 g/mol.

Step-by-step explanation:

The problem involves determining the molar mass of an unknown acid H2X by using its reaction with a sodium hydroxide (NaOH) solution. The acid releases two hydrogen ions when it reacts completely with NaOH.

First, we calculate the moles of NaOH used:

• Number of moles of NaOH = Volume (L) × Molarity (M)
• Number of moles of NaOH = 0.035 L × 0.400 M = 0.0140 moles of NaOH

Because H2X gives two H+ ions and it reacts with NaOH in a 1:2 ratio, the moles of H2X would be half the moles of NaOH:

• Number of moles of H2X = 0.0140 moles of NaOH ÷ 2 = 0.00700 moles of H2X

Now, we can find the molar mass of H2X:

• Molar mass of H2X = Mass of H2X sample (g) ÷ Number of moles of H2X
• Molar mass of H2X = 1.50 g ÷ 0.00700 moles = 214.29 g/mol (rounded to two decimal places)