A volume of 150mL of 0.35M HCl is to be prepared from 80% HCl stock solution. (Density of HCl = 1.191g/mL). Calculate the molarity of 80% HCl stock solution.
density 1.191 g/mL.
mass 1000 mL = 1.191 g/mL x 1000 mL = 1191 g.
mass HCl in that 1L = 1191 x 0.80 = 952.8 g HCl.
mols HCl = grams/molar mass = 952.8/36.46 = 26.13 mols HCl.
M = mols/L = 26.13/L = 26.13M BUT let me point out that this can't be so. The calculations are right so this will show you the procedure by which it's done; however, the most concd you can get HCl is about 38% HCl. There is no such animal as 80% HCl. Concentrated HCl solutions available commercially, containing 36-38% HCl are about 12 M.
To calculate the molarity of the 80% HCl stock solution, we need to know the amount of solute (HCl) and the volume of the solution.
Firstly, let's determine the mass of HCl present in the 150mL solution using the density of HCl. Since the density of HCl is given as 1.191g/mL, we can calculate the mass of HCl using the formula: mass = density × volume.
mass = 1.191g/mL × 150mL
mass = 178.65g
Next, we need to find the mols of HCl in the solution using the formula: moles = mass / molecular weight.
The molecular weight of HCl is the sum of the atomic weights of hydrogen (H) and chlorine (Cl), which is approximately 1g/mol + 35.5g/mol = 36.5g/mol.
moles = 178.65g / 36.5g/mol
moles ≈ 4.90mol
Finally, let's calculate the molarity of the 80% HCl stock solution by dividing the number of moles by the volume of the solution in liters. Remember that molarity is defined as moles of solute divided by liters of solution.
Molarity (M) = moles / volume (L)
Molarity = 4.90mol / 0.150L
Molarity ≈ 32.67M
Therefore, the molarity of the 80% HCl stock solution is approximately 32.67M.