What is the concentration of a HCl solution if 20.0 mL of the solution is neutralized by
15.0 mL of a 0.10 M Ca(OH)2 solution?
To find the concentration of the HCl solution, you can use the concept of stoichiometry.
Here's how you can approach this problem:
Step 1: Write the balanced chemical equation for the reaction between HCl and Ca(OH)2. The equation is as follows:
2HCl + Ca(OH)2 -> CaCl2 + 2H2O
Step 2: Determine the stoichiometry of the reaction. From the balanced chemical equation, you can see that 2 moles of HCl react with 1 mole of Ca(OH)2.
Step 3: Calculate the number of moles of Ca(OH)2 used. The concentration of the Ca(OH)2 solution is given as 0.10 M, which means that there are 0.10 moles of Ca(OH)2 in 1 liter. As you used 15.0 mL (0.015 L) of the Ca(OH)2 solution, you can calculate:
moles of Ca(OH)2 = concentration × volume
moles of Ca(OH)2 = 0.10 M × 0.015 L = 0.0015 moles
Step 4: Use the stoichiometry of the reaction to determine the number of moles of HCl that reacted. From the balanced equation, you know that 2 moles of HCl react with 1 mole of Ca(OH)2. Therefore, the number of moles of HCl used can be calculated as:
moles of HCl = 2 × moles of Ca(OH)2
moles of HCl = 2 × 0.0015 moles = 0.003 moles
Step 5: Calculate the concentration of the HCl solution. You used 20.0 mL (0.020 L) of the HCl solution, so the concentration can be calculated as:
concentration of HCl = moles of HCl / volume
concentration of HCl = 0.003 moles / 0.020 L = 0.15 M
Therefore, the concentration of the HCl solution is 0.15 M.