Calculate the molarity of a hydrochloric acid solution in 70 ml of which contains 8 grams of hydrochloric acid.

Given:
V solution (HCl) = 70 ml
m (HCl) = 8 g
To find:
C solution (HCl) -?
Decision:
1) find the amount of HCl substance:
n (HCl) = m (HCl) / Mr (HCl) = 8 / 36.5 = 0.22 mol
2) find the molarity of the HCl solution:
C solution (HCl) = n (HCl) / V solution (HCl) = 0.22 / 0.07 = 3.14 mol / l
Answer: The molarity of the HCl solution is 3.14 mol / l.