How to Prepare 0.5 N and 1 N HCl

Concentrated HCl

      Concentrated HCl has strength of approximately 31-36%,in case of 36% means 360 ml HCl is present  per 1000 ml of solution for 32 % HCl, 320 ml of HCl is present per 1000 ml of solution. 

      For preparing dilute normal solutions from concentrated HCl we need to calculate its volume according to its percent strength required to mix with water. To calculate required volume of concentrated HCl to prepare different normal solutions  follow below mentioned steps.  normally HCl found in chemistry labs is of 36% so let us take example of 36% HCl for calculation.

Step 1

Calculate weight of HCl in 360 ml of HCl by multiplying it with specific gravity of 36% HCl i.e. 1.1789

360 x 1.178=424.08 gm

 means 360 ml of HCl = 424.08 gm

Step 2

Calculate no. of moles in 424.08 gm of HCl by using formula

                                   No. of moles =given weight/molecular mass of HCl

                                                     N=424.08/36.5 =11.6 moles

as HCl has only one replaceable Hydrogen ion its gram equivalent weight and molcular weight is same and hence Normality and Molarity is same as well. Means no. of moles is equal to gram equivalents which ultimately is its Normailty.

Hence, Normality of 36% HCl = No.of moles = 11.6 N

Step 3

Prepare 1N HCl by using Normality equation- 

let us calculate volume of concentrated HCl required to prepare 100 ml 1 N HCl.

(Conc. HCl)N1 V1= N2V2 (1N HCl)

11.6N x V1= 1N x 100ml

V1 =1 x 100/11.6

V1  = 8.6 ml

So to prepare 100 ml 1 N HCl from concentrated HCl  8.6 ml of concentrated Acid is diluted up to 100 ml with water.

Different normal solutions can be prepared  by using the above equation by changing the value of required volume and normality of the required solution .e.g.

To prepare 500 ml of 0.5 N HCl

(Conc. HCl)N1 V1= N2V2 (1N HCl)

11.6 N x V1= 0.5 N  x 500 ml

V1 =0.5 x 500/11.6

V1  = 21.5 ml

So to prepare 500 ml of 0.5 N HCl, 21.5 ml of concentrated Acid is diluted up to 500 ml.

It is not necessary to calculate every time no. of moles to calculate volume if u remember Normality of concentrated HCl i.e. 11.6 N, then volume can be easily calculated by direct from normality equation for different volume and normality.