Question

a) Blue Crystals of a substance changed their colour on heating in a
closed test tube but regained it after sometime when they were allowed
to cool down. Name the substance and write its formula and explain the
phenomenon involved.
(b) Name the compound whose one formula unit is associated with 10
water molecules. How is it prepared? Give equations of related
reactions. Give two uses of the compound..

Answer 1

Answer:

A : magnesium oxide

"mgO2

Explanation:

heat is important for every reactants