The standard coagulant used in water treatment is:

Alum is the standard coagulant used in water treatment to clump fine suspended particles.

Hypochloride is a disinfectant term, not a coagulant used to settle turbidity.

Chlorine disinfects water by killing microbes but does not coagulate particles.

Aluminium as a bare metal is not the reagent added; it is the aluminium salt alum.

Coagulation forms larger flocs that settle out during clarification.

Alum is aluminium potassium sulphate, widely used in municipal water works.