Question

How much 38%Hcl will be used to prepare N/3.05 solution in 2litre water.

Answer 1

You must know the density of the HCl. The usual density of 38% HCl is about 1.19 g/mL. Therefore, the normality of 38% HCl is approximately as follows:
1.19 g/mL x 1000 mL x 0.38 x (1 equiv/36.5g) = about 12.4N.
Now apply the dilution formula.
c1v1 = c2v2
c = concn
v = volume
(Note:N/3.05 = 0.328 N

12.4N*v mL =0.328N*2000mL
Solve for v mL.
Place v mL in a 2L volumetric flask, add water to the mark on the flask and mix thoroughly.