Question

what is mean by alum

Answer 1

a colorless styptic compound which is a hydrated double sulphate of aluminium and pottasium.. 
uses of alum :
-> pottasium alum is thecoomon alum of commerce, altough soda alum. ferric alum, and amonium alum are manufactured.
-> alum in block form can be used as a blood coagulant 
-> in nigeria it is used in the removal of snail slime before cooking
->solutions containing alum may be used to treat cloth, wood, paper materials to increase their resistance in fire
-> alum is also used in fire extinguishers to smother chemical and oil fires

Answer 2

alum is a chemical compound.the chemical formula of alum is KAl(SO4)2.

it is a water soluble compound.

it is used to purify water.

the process in which alum is used to settle harmful particles(sedimentation) is known as loading.