Question

Which of the following is an example of hydrated substance?
A) Washing soda
B) Gypsum
C) Blue vitriol
D) All of the above

Answer 1

Hint: Hydrated substances are compounds containing water in the form of $H_2O$ molecules, usually, but not always, with a definite content of water by weight. The best-known hydrates are crystalline solids that lose their fundamental structures upon removal of the bound water.

Complete answer:
In this question three compounds are given that are washing soda, Gypsum & Blue vitriol. Let’s discuss all the options one by one-
Option (A) is washing soda. The chemical formula of Washing soda - \[N{a_2}C{O_{3}}.10H_2O\]
Option (B) is Gypsum. The chemical formula of Gypsum- \[CaS{O_4}.2{H_2}O\]
Option (C) is blue vitriol. The chemical formula of Blue vitriol -\[CuS{O_4}.5{H_{2}}O\]
 We can clearly observe in all above chemical formulas that they contain water molecules & the substances which contain water molecules are hydrated substances.

Hence all options are correct and the correct choice is- Option (D).

Additional Information: There are various examples of hydrated compounds. Some of these with their molecular formula are as follows-
Borax (sodium tetraborate decahydrate)- \[N{a_2}{B_4}{O_7}.10{H_2}O\]
Glauber’s salt (sodium sulfate decahydrate) - \[N{a_2}S{O_4}.10{H_2}O\]
Epsom salt- \[MgS{O_4}.7{H_2}O\]

Note: Students may confuse in formula if the names have similar types of pronunciation. We can take the example of Epsom & Gypsum. We already have discussed the formula of both compounds above. Blue vitriol and green vitriol can also create confusion. The chemical formula of green vitriol is \[FeS{O_4}.7{H_2}O\].