0.15g of hydrogen chloride (HCl) is dissolved in water to make 6.5L of solution. What is the pH of the resulting hydrochloric acid solution?
0.15g/molar mass = mols
M = mols/6.5L
pH = -log(HCl)
To determine the pH of the hydrochloric acid solution, we need to calculate the concentration of H+ ions in the solution.
Step 1: Calculate the molarity (M) of the hydrochloric acid solution.
Molarity (M) is calculated using the formula:
M = (moles of solute) / (volume of solution in liters)
First, we convert the mass of hydrogen chloride (HCl) to moles.
Molecular weight of HCl = 1 g/mol (H) + 35.5 g/mol (Cl) = 36.5 g/mol
moles of HCl = mass / molecular weight
= 0.15 g / 36.5 g/mol
≈ 0.0041 mol
Now, we can calculate the molarity of the HCl solution.
Molarity of HCl solution = moles of HCl / volume of solution (in L)
= 0.0041 mol / 6.5 L
≈ 0.00063 M
Step 2: Calculate the concentration of H+ ions.
Since hydrochloric acid (HCl) fully dissociates in water, the concentration of H+ ions is equal to the molarity of the HCl solution.
Concentration of H+ ions = 0.00063 M
Step 3: Calculate the pH.
The pH is a measure of the concentration of H+ ions in a solution, which is given by the formula:
pH = -log[H+]
Therefore, the pH of the hydrochloric acid solution can be calculated as:
pH = -log(0.00063)
≈ 3.20
Thus, the pH of the resulting hydrochloric acid solution is approximately 3.20.
To calculate the pH of a solution, you need to know the concentration of hydrogen ions (H+) in the solution. In this case, we need to calculate the concentration of H+ ions in the hydrochloric acid solution.
First, we need to convert the given mass of hydrogen chloride to moles. You can use the molecular weight of hydrogen chloride to do this. The molecular weight of HCl is 36.46 g/mol.
moles of HCl = mass of HCl / molecular weight of HCl
moles of HCl = 0.15 g / 36.46 g/mol
Next, we need to calculate the molarity (M) of the solution by dividing the moles of HCl by the volume of the solution in liters.
Molarity = moles of HCl / volume of solution (in L)
Molarity = (0.15 g / 36.46 g/mol) / 6.5 L
Now that we have the molarity of the HCl solution, we can calculate the concentration of H+ ions. Since hydrochloric acid is a strong acid, it completely ionizes in water, so the concentration of H+ ions is equal to the molarity of the HCl solution.
Concentration of H+ ions = Molarity of HCl solution
Now, to calculate the pH, we need to take the negative logarithm (base 10) of the H+ concentration.
pH = -log[H+]
Therefore, the pH of the resulting hydrochloric acid solution can be calculated using the concentration of H+ ions.