Question

Find the molarity of the calcium hydroxide solution, given that 428 mL of it is neutralized in a titration by 115 mL of 6.7 x 10-3 M nitric acid.

Answer 1

To find the molarity of the calcium hydroxide solution, we first need to determine the number of moles of nitric acid used in the titration.

Moles of nitric acid = Molarity x Volume (in L)
Moles of nitric acid = 6.7 x 10-3 mol/L x 0.115 L
Moles of nitric acid = 7.71 x 10^-4 mol

Since calcium hydroxide reacts with 2 moles of nitric acid according to the balanced chemical equation, the number of moles of calcium hydroxide present in the solution is half the moles of nitric acid used in the titration.

Moles of calcium hydroxide = 1/2 x 7.71 x 10^-4 mol
Moles of calcium hydroxide = 3.855 x 10^-4 mol

Now, we can calculate the molarity of the calcium hydroxide solution:

Molarity of calcium hydroxide solution = Moles of solute / Volume of solution (in L)
Molarity of calcium hydroxide solution = 3.855 x 10^-4 mol / 0.428 L
Molarity of calcium hydroxide solution ≈ 9.01 x 10^-4 M

Therefore, the molarity of the calcium hydroxide solution is approximately 9.01 x 10^-4 M.