Calculate the mass of anhydrous HCl....?

Question

calculate the mass of anhydrous HCl in 5.00 mL of concentrated hydrochloric acid (density 1.19g/mL) containing 37.23% by weight.

i dont really get the wording of the question. please explain and help

me with this problem

Answer 1

Anhydrous HCl is a gas which is soluble in water.  When the gas dissolves, it ionizes into Hydrogen cations (H+) and Chloride anions (Cl-).  This is why (or how) it remains in solution.  Aqueous Hydrogen chloride is called Hydrochloric acid.

You are given 5.00 mL of a Hydrochloric acid solution.  Each mL has a mass of 1.19 g (from the density given).  The total mass of the solution is  

5.00 mL * 1.19 g/mL = 5.95 g

Of this 5.95 g, you know that 37.23 percent is HCl (it is called by weight, but it really means percent by mass).  The total mass of the HCl is then

5.95 g * 0.3723 = 2.2152 g of HCl (or about 2.22 grams)