The minimum concentration of an electrolyte required to cause coagulation of a sol is called its flocculation value.It is expressed in millimoles per litre.If the flocculation value of `MgSO_4` for standard `As_2S_3` sol is 3.33. How many milligrams of `MgSO_4` is to be added to 20ml standard `As_2S_3` sol so that flocculation just state ?

Answer

8

Explanation

Flocculation value =3.33 millimoles/L
Millimoles required for 20 mL `=3.33/1000xx20`
Mass in milligrams required for 20 mL`=3.33/100xx20xx120=8` mg