How do you write “calcium hydroxide + phosphoric acid yield calcium phosphate in water”?

Hint:In order to write the chemical reaction for “calcium hydroxide + phosphoric acid yield calcium phosphate in water”, we must first know the chemical formula for each of the given chemical compounds.

Complete answer:
Let us first write the chemical formula for all given chemical compounds.
The chemical formula for phosphoric acid is \[{H_3}P{O_4}\]and it is a weak acid.
The chemical formula for calcium hydroxide is \[Ca{(OH)_2}\]and it is a strong base.
The chemical formula for calcium phosphate is \[C{a_3}{(P{O_4})_2}\] and it is an insoluble salt.
The chemical formula for water is \[{H_2}O\].
 The strong base (\[Ca{(OH)_2}\]) will react with weak acid (\[{H_3}P{O_4}\]) to give an insoluble salt (\[C{a_3}{(P{O_4})_2}\]) and water (\[{H_2}O\]) and this reaction is known as the neutralisation reaction. The reaction is given below:
\[Ca{(OH)_2} + {H_3}P{O_4} \to C{a_3}{(P{O_4})_2} + {H_2}O\]
We have to balance the above given reaction as:
\[3Ca{(OH)_2} + 2{H_3}P{O_4} \to C{a_3}{(P{O_4})_2} + 6{H_2}O\]

Additional Information:
Let us see some of the characteristics of Calcium phosphate.
- Calcium phosphate appears as white crystalline or amorphous powder which is tasteless and odourless.
- It is soluble in nitric and hydrochloric acid but only slightly soluble in water.
- It is used in antacid, dietary supplements, production of fertilisers, manufacture of luminescent materials etc.

Note:
One thing we have to remember is that we should never forget to balance the chemical reaction after writing. Because it can make the chemical reaction incomplete or incorrect. Therefore, always remember to balance the reaction.