Question

How do you prepare 2M HCl solution?

Answer 1

Solution: 167 mL conc. HCl is added in 833 mL of water.

Calculations:

Part A) Conversion of % w/w HCl to M HCl:

>> The percentage composition of HCl is 37%

Thus, % w/w of HCl = 37

Density of HCl = 1.19 kg/L
Molecular weight of HCl = 36.5 g/mol

Thus,

M = (37% HCl x 1.19 kg L-1)/ 36.5 g mol-1

M = 0.44 kg L-1 / 36.5 g mol-1
M = 12 mol/L

Thus, concentrated HCl 37% is 12 M

Part B) Molarity to volume calculation.

>> According to molarity equation,

For preparation of 1L of solution,

M1V1 = M2V2

M1 = 12 M

M2 = 2 M

V1 = ?

V2 = 1L

Thus,

12 M x V1 = 2 M x 1L

V1 = 2 / 12 = 0.167 L

V1 = 167 mL

Therefore, 167 mL of 37 % HCl is added to 833 ml (1000 - 167) mL of water.