Question

What is the name for $Ca{(OH)_2}$ ?

Answer 1

Hint: Bases are those compounds producing hydroxide ions $(O{H^ - })$ on dissolving in water. The nomenclature of bases is not so difficult. It includes naming the cation followed by the term ‘hydroxide’ since all of them contain $O{H^ - }$ ions. One of the most common bases is sodium hydroxide $(NaOH)$.The compound is neutral so the +1 charge on $N{a^ + }$ is balanced by 1 hydroxide ion, so the formula becomes $NaOH$.

Complete answer:
The IUPAC name for $Ca{(OH)_2}$ is Calcium Hydroxide and it is also called Slaked lime (Since it is formed by mixing or slaking quicklime i.e.$CaO$ with water). It has many other names like caustic lime, hydrated lime, builder’s lime, pickling lime and slack lime.

Additional Information:
Calcium hydroxide is a strong Alkali. It is an inorganic compound which is present in solid state. Its saturated aqueous solution is called Lime water. Calcium hydroxide contains ionic bonds between Calcium and hydroxide ions and hence holds strongly. It is slightly soluble in water. Its melting point is 852K.Its molecular weight is 74.08g/mol. It contains Calcium atoms bonded with ionic bonds to 2 hydroxide ions. In solid state it exists in Polymeric form bonded with hydrogen bonds.
It is prepared by reacting Calcium oxide (lime or quicklime) in water as follows-
$CaO + {H_2}O \to Ca{(OH)_2}$
The dissociation reaction of calcium hydroxide occurs as follows-
$Ca{(OH)_2} \to C{a^{ + 2}} + 2O{H^ - }$
The solution is basic and the pH of the solution is 12.5.

Note:
Calcium Hydroxide has many Industrial applications. It is very useful in sewage treatment, dental treatment, paper industries and food industries like in the pickling process. Calcium hydroxide is very useful when taken in low concentration but in high concentration causes toxicity and poisoning in the human body.