Question

A 500 ml water sample has a hardness equivalent to 10.5 ml of 0.5 n caso4. what is the hardness in ppm.​

Answer 1

Answer:

Normality = No. of gms equivalent per litre 

No. of gm equivalents = Normality * volume of CaSO4/1000ml 

No. of gm equivalent = wt. in gms / eq wt = 0.1 x 50/1000 = 5 x 10-3

Wt. in gms in 500 ml of water = No. of gms equivalent x eq. wt. of CaSO4 

Wt. in gms in 1000 ml of water = 2 x 5 x 10-3 x eq. wt of CaSO4

Hardness due to CaSO4 = Strength of CaSO4 x Chem eq. of CaCO3 / Chem eq. of CaSO4

                                        =10-2 x 50 g/I 

                                        = 500 mg/I 

                                        = 500 ppm