chemistry
posted by m .
anyone help me . .what volume of concentrated HCL solution whoch is 36% by mass and has a density of 1.179 g/ml , should be used to make 4.7 L of hcl solution with a pH of 1.8 ?

First you want to calculate the (HCl). That's
density x 1000 mL x (%/100) x 1/molar mass = M
1.179 x 1000 x 0.36 x (1/36.5) =11.6 M
Then c1v1 = c2v2
What H^+ do you want for pH = 1.8? That is 1.8 = log(H^+) = about 0.0158
c = concn
v = volume
11.6 x v = 0.0158 x 4,700 mL
v = ? mL. 
11.79