Question

Write the name and chemical formula of bases present in lime water.

Answer 1

A base is a chemical compound which has a pH value >7, and the best way to identify a base is to identify its ability to donate electrons, or its ability to liberate ${\text{O}}{{\text{H}}^ - }$ions on dissolution. Limestone is called ‘Chuna pathar’ in Hindi and is used in many Indian households as a complementary ingredient with betel leaf and betel nut.

Complete step-by-step answer: Lime water is made by a mixture of limestone and water as the solvent.
Limestone is a naturally occurring sedimentary rock that mainly consists of minerals, and these minerals are just carbonated forms of calcium ${\text{CaC}}{{\text{O}}_3}$.
The chemical reaction between water and limestone can be written as;
${\text{CaC}}{{\text{O}}_3}{\text{ + }}{{\text{H}}_2}{\text{O}} \to {\text{Ca(OH}}{{\text{)}}_2}{\text{ + C}}{{\text{O}}_2}$
Calcium hydroxide ${\text{Ca(OH}}{{\text{)}}_2}$, can acts as a base since it can donate ${\text{O}}{{\text{H}}^ - }$ ions.
Hence, the base present in the lime water is calcium hydroxide with the chemical formula ${\text{Ca(OH}}{{\text{)}}_2}$.

Additional information: Calcium carbonate has some many industrial uses;
i.It is used in the cement industry as a raw material.
ii.It is also a major component of our toothpaste as our teeth are made up of calcium.
iii.It is also used as an additive in food industries as a source of calcium.

Note: There are different definitions of the base, given by different scientists, we have lewis's base, Bronsted Lowry bases, an Arrhenius base, and oftentimes these three could be confusing hence it is important to have a clear idea about all these concepts with appropriate examples.