Commercial grade hcl solutions are typically 39.0% (by mass) hcl in water. determine the molarity of the hcl, if the solution has a density of 1.20 g/ml.

To make computations easier, let us assume that there is 1 liter solution of the sample.

So using the density formula to know what the mass of this sample would be:

1 L x 1000 mL / 1L x 1.20g / 1 mL = 1120g

Now use the percent concentration by mass to know how many grams of HCl you can have:

1120 g sol x 39 g HCl / 100 g = 313.6 g HCL

To determine the solution's molarity, use the molar mass to know the number of moles present:

313.6g x 1 mole / 36.46g = 8.60 moles

since the sample has a volume of 1 L, the molarity is:

C = n / V = 8.60 moles / 1.0 L = 8.60 M

To get the solution's molarity, determine the mass of water.

Msol = Mwater + Macid

Mwater = Msol - Macid = 1120 - 313.6 = 806.4 g

The molarity will be:

b = n / Mwater = 8.60 moles / 806.4 x 10^-3 = 10.66 molal

the solution's molarity will be equal to its normality since HCl acid can only release one mole of protons per mole of acid

Normality = 8.6 N