How many mL of concentrated HCl(aq) (36% HCL by mass, d=1.18g/mL_ are required to produce 12.5 L of a solution with ph = 2.10?
First I started with finding out the concentration of [H30+] and for that I got 7.94 x 10^-3 but I don't know how to continue.
I think the easiest way to solve this problem is to a)determine molarity of the HCl solution.
b) apply the dilution formula.
a) 1.18g/mL x 1000 mL = mass of 1 L HCl soln.
How much is HCl? That will be mass of 1L x 0.36 = ?? g HCl
How many moles is that. That will be grams HCl/molar mass HCl. That will be the molarity. Then L1 x M1 = 12.5L x 7.94E-3. Then convert L to mL.
Alright thanks so much.
To find the amount of concentrated HCl needed to produce a solution with a pH of 2.10, you can follow these steps:
Step 1: Calculate the concentration of H3O+ ions in the solution.
Given that the pH is 2.10, we can convert it to [H3O+].
pH = -log[H3O+]
2.10 = -log[H3O+]
[H3O+] = 10^(-pH) = 10^(-2.10) = 7.94 x 10^(-3) M
Step 2: Convert the concentration of H3O+ into moles per liter (M).
The molar concentration of H3O+ is equal to the moles of H3O+ ions divided by the volume in liters.
Molarity (M) = moles of solute / liters of solution
The volume of the solution is given as 12.5 L, so the moles of H3O+ can be calculated as follows:
Moles of H3O+ = Molarity (M) x Volume (L)
Moles of H3O+ = 7.94 x 10^(-3) M x 12.5 L = 9.92 x 10^(-2) moles
Step 3: Calculate the number of grams of HCl required.
The concentration of HCl is given as 36% by mass, which means 36 g of HCl is present in 100 g of HCl solution.
To calculate the mass of HCl required, we can use the molar mass of HCl, which is approximately 36.46 g/mol.
Mass of HCl = moles of HCl x molar mass of HCl
Mass of HCl = 9.92 x 10^(-2) moles x 36.46 g/mol = 3.61 g
Step 4: Calculate the volume of concentrated HCl.
To convert the mass of HCl into volume, we can use the density of HCl. The density given is 1.18 g/mL.
Volume (mL) = mass (g) / density (g/mL)
Volume = 3.61 g / 1.18 g/mL ≈ 3.06 mL
Therefore, approximately 3.06 mL of concentrated HCl (36% HCl by mass, d=1.18 g/mL) is required to produce 12.5 L of a solution with a pH of 2.10.
To continue solving the problem, you can use the concentration of [H3O+] to find the concentration of HCl in the solution. Once you have the concentration of HCl, you can calculate the moles of HCl needed to prepare 12.5 L of solution, and finally convert it to milliliters.
Here's a step-by-step breakdown of how to proceed:
Step 1: Calculate the concentration of HCl in the solution:
Since pH = -log[H3O+], you can rearrange the equation to find the concentration of [H3O+]:
[H3O+] = 10^(-pH)
Substituting the given pH value of 2.10, you get:
[H3O+] = 10^(-2.10)
[H3O+] = 0.00794 M
Step 2: Determine the concentration of HCl:
The molar concentration of HCl is the same as the concentration of [H3O+], as HCl dissociates into H3O+ ions. Therefore, the concentration of HCl is also 0.00794 M.
Step 3: Calculate the moles of HCl:
Moles = concentration × volume
Moles = 0.00794 mol/L × 12.5 L
Moles = 0.09925 mol
Step 4: Convert moles to grams of HCl:
To convert moles to grams, you need to use the molar mass of HCl, which is 36.5 g/mol. Multiply the moles by the molar mass:
Mass = moles × molar mass
Mass = 0.09925 mol × 36.5 g/mol
Mass = 3.621 g
Step 5: Convert grams to milliliters of concentrated HCl:
To do this, you need to know the density of the concentrated HCl solution, which is given as 1.18 g/mL. Use the formula:
Volume (mL) = Mass (g) / Density (g/mL)
Volume = 3.621 g / 1.18 g/mL
Volume = 3.07 mL
Therefore, you would need approximately 3.07 mL of concentrated HCl(aq) (36% HCl by mass, d=1.18 g/mL) to produce 12.5 L of a solution with pH 2.10.