Question

In an experiment to determine the concentration of a barium hydroxide solution, a student placed a nitric acid solution in an Erlenmeyer flask along with some distilled water and a few drops of phenolphthalein indicator. The acid solution was then titrated with barium hydroxide solution from a buret until a faint pink color was reached. The following data was recorded: Molarity of nitric acid solution = 0.219 M Volume of nitric acid solution used = 13.4 mL Initial buret reading = 18.3 mL Final buret reading = 31.3 mL b) Use the lab data above to calculate the molarity of the barium hydroxide solution to the correct number of significant figures.

Answer 1

Step-by-step explanation:

To calculate the molarity of the barium hydroxide solution, we can use the concept of stoichiometry and the balanced chemical equation for the reaction between nitric acid (HNO3) and barium hydroxide (Ba(OH)2).

The balanced chemical equation for the reaction is:

2 HNO3 + Ba(OH)2 → Ba(NO3)2 + 2 H2O

From the balanced equation, we can see that the stoichiometric ratio between nitric acid and barium hydroxide is 2:1. This means that for every 2 moles of nitric acid used, 1 mole of barium hydroxide is consumed.

Let's calculate the number of moles of nitric acid used in the titration:

Molarity of nitric acid solution = 0.219 M

Volume of nitric acid solution used = 13.4 mL = 0.0134 L

Using the formula:

moles of solute = molarity × volume

moles of nitric acid = 0.219 M × 0.0134 L = 0.0029326 mol

Since the stoichiometric ratio between nitric acid and barium hydroxide is 2:1, the number of moles of barium hydroxide is half of the moles of nitric acid used in the reaction.

moles of barium hydroxide = 0.0029326 mol / 2 = 0.0014663 mol

Now, let's calculate the volume of barium hydroxide solution used in the titration:

Initial buret reading = 18.3 mL

Final buret reading = 31.3 mL

Volume of barium hydroxide solution used = Final buret reading - Initial buret reading

= 31.3 mL - 18.3 mL

= 13 mL = 0.013 L

Finally, let's calculate the molarity of the barium hydroxide solution:

Molarity of barium hydroxide solution = moles of barium hydroxide / volume of barium hydroxide solution used

Molarity of barium hydroxide solution = 0.0014663 mol / 0.013 L

= 0.1128 M

Therefore, the molarity of the barium hydroxide solution, to the correct number of significant figures, is 0.1128 M.