50.0 mL of an HCl solution with a pH of 3.5 neutralizes 200.0 mL of a Ca(OH)2
solution. What is the molarity of the Ca(OH)2 solution?
pH = -log (H^+). Substitute and solve for M HCl
Then follow the instructions above for HCl vs NaOH problem.
To find the molarity of the Ca(OH)2 solution, we need to calculate the number of moles of HCl used in the neutralization reaction and then use stoichiometry to determine the number of moles of Ca(OH)2.
First, let's calculate the number of moles of HCl using its volume and pH value.
pH is a measure of the acidity or basicity of a solution and can be used to calculate the concentration of hydrogen ions (H+). The formula to calculate pH is:
pH = -log[H+]
To find the concentration of H+ (in moles per liter), we need to calculate the antilog of the negative pH value:
[H+] = 10^(-pH)
Given that the pH of the HCl solution is 3.5, we have:
[H+] = 10^(-3.5)
Next, we need to convert the volume of the HCl solution to liters:
Volume (L) = 50.0 mL = 50.0 mL * (1 L / 1000 mL) = 0.050 L
Now, we can calculate the number of moles of HCl:
Moles of HCl = [H+] * Volume (L)
Moles of HCl = 10^(-3.5) * 0.050 L
Next, we need to use the balanced chemical equation for the neutralization reaction between HCl and Ca(OH)2 to determine the stoichiometric relationship between them.
The balanced equation for the neutralization reaction between HCl and Ca(OH)2 is:
2 HCl + Ca(OH)2 → CaCl2 + 2 H2O
According to the stoichiometry of this equation, 2 moles of HCl react with 1 mole of Ca(OH)2.
Therefore, the number of moles of Ca(OH)2 can be calculated as:
Moles of Ca(OH)2 = (Moles of HCl * 1 mole of Ca(OH)2) / (2 moles of HCl)
Finally, we can find the molarity of the Ca(OH)2 solution by dividing the number of moles of Ca(OH)2 by the volume (in liters) of the Ca(OH)2 solution.
Molarity of the Ca(OH)2 solution = Moles of Ca(OH)2 / Volume (L) of Ca(OH)2 solution
Substituting the calculated values, we can now solve for the molarity of the Ca(OH)2 solution.