Question

0.2 Grams of HCL is dissolved in 0.8g of water. The density of the solution formed is 1.10g/ml.

What is the molarity of the solution????

%HCl = [0.2/0.2+0.8)]x100 = 20%
Density = 1.10 g/mL.
The mass of 1,000 mL is 1.10 g/mL x 1,000 mL = 1100 grams.
Mass HCl in the 1100 g is 1100 x 0.2 = 220 grams (the 0.2 is the 20%).
Convert 220 grams to mols.
That is mols/1,000 mL or mols/L and that is molarity.