42nd B.P.S.C. (Pre) 1997-98
The formula of Plaster of Paris is-
aCaSO4
b(CaSO4)2·H2O✓ Correct
cCaSO4·H2O
dCaSO4·2H2O
Explanation
The chemical formula of Plaster of Paris is CaSO4·$\frac{1}{2}$H2O (calcium sulfate hemihydrate). It is formed by heating gypsum (calcium sulfate dihydrate). However, as per the options, it can also be written equivalently as (CaSO4)2·H2O.
general-science