What is the molarity of calcium hydroxide if 20.0 mL of it is neutralized by 28.0 mL of 0.56 M hydrobromic acid?
To find the molarity of the calcium hydroxide solution, we need to first determine the number of moles of hydrobromic acid used in the neutralization reaction.
From the given information, we know that the volume of the hydrobromic acid solution is 28.0 mL and its molarity is 0.56 M. We can use the formula:
Molarity = moles of solute / volume of solution
Rearranging the formula to solve for moles of solute, we have:
moles of solute = Molarity x volume of solution
moles of hydrobromic acid = 0.56 mol/L x 0.028 L
moles of hydrobromic acid = 0.01568 mol
Since the neutralization reaction between calcium hydroxide and hydrobromic acid is 1:2 (1 mol of Ca(OH)2 reacts with 2 mol of HBr), the moles of calcium hydroxide is twice the moles of hydrobromic acid.
moles of calcium hydroxide = 2 x moles of hydrobromic acid
moles of calcium hydroxide = 2 x 0.01568 mol
moles of calcium hydroxide = 0.03136 mol
Finally, we calculate the molarity of the calcium hydroxide solution using the formula:
Molarity = moles of solute / volume of solution
Molarity = 0.03136 mol / 0.020 L
Molarity = 1.568 M
Therefore, the molarity of the calcium hydroxide solution is 1.568 M.