Coagulation value = no. of millimoles of KCl/vol. of Sol. in litre = (0.5 x 10 x 1000)/50

Coagulation Value of KCl

Introduction:

Coagulation is the process of precipitation of colloidal particles from suspension due to the addition of an electrolyte. The minimum concentration of electrolyte required to coagulate a given colloidal sol is called its coagulation value.

Given:

- Volume of ferric hydroxide sol = 50 ml
- Volume of 0.5 M KCl required for coagulation = 10 ml

Calculation:

The coagulation value of KCl can be calculated as follows:

- Number of moles of KCl required for coagulation = Molarity x Volume = 0.5 x 0.01 = 0.005 moles
- Number of moles of Fe(OH)3 in 50 ml of sol can be calculated using the formula:

n = C x V

where n is the number of moles, C is the concentration and V is the volume.

- The concentration of Fe(OH)3 can be assumed to be 1 M, as it is not given explicitly in the question. Therefore, the number of moles of Fe(OH)3 in 50 ml of sol is:

n = 1 x 0.05 = 0.05 moles

- The coagulation value of KCl can be calculated using the formula:

CV = (nKCl / nFe(OH)3) x MWFe(OH)3 / MWKCl

where CV is the coagulation value, nKCl is the number of moles of KCl required for coagulation, nFe(OH)3 is the number of moles of Fe(OH)3 in the sol, MWFe(OH)3 is the molar mass of Fe(OH)3 and MWKCl is the molar mass of KCl.

- The molar mass of Fe(OH)3 is 106.87 g/mol and the molar mass of KCl is 74.55 g/mol. Substituting the values, we get:

CV = (0.005 / 0.05) x (106.87 / 74.55) = 1.53

Therefore, the coagulation value of KCl is 1.53.

Conclusion:

The coagulation value of KCl is 1.53. This means that a concentration of 1.53 moles of KCl per litre of ferric hydroxide sol is required to coagulate it.