Question

A tribasic acid is
A.Oxalic acid
B.Tartaric acid
C.Lactic acid
D.Citric acid

Answer 1

Hint: If an acid contains replaceable hydrogen atoms then it is called basicity and a tribasic acid is one that has three replaceable ${{H}^{+}}$ions. From the given option just we have to find their structure to see that in which acid contains three hydrogen ions to donate to a base in a redox reaction.

Complete answer:When a component is dissolved in water it releases hydrogen ions,${{H}^{+}}$called acid. Generally, basicity is the number of replaceable ${{H}^{+}}$ions when an acid dissolves in water. If an acid contains one replaceable ${{H}^{+}}$ion is called monobasic acid. A dibasic acid contains two replaceable ${{H}^{+}}$ions and a tribasic acid contains three replaceable ${{H}^{+}}$ions.

Oxalic acid has a chemical formula $HOOC-COOH$ and it is a polyprotic acid and basicity is equal to $2$. Hence it is a dibasic acid.


The chemical formula of tartaric acid is ${{[CH(OH)COOH]}_{2}}$. It is also a dibasic acid as it has two replaceable ${{H}^{+}}$ions.


Lactic acid is an organic compound having IUPAC name $2-$hydroxy propanoic acid and chemical formula $C{{H}_{3}}CH(OH)COOH$. As it can donate one ${{H}^{+}}$ion to a base thus it is a monobasic acid.


Finally citric acid is an organic compound with a chemical formula $HOOC(HO)C{{(C{{H}_{2}}C{{O}_{2}}H)}_{2}}$. Citric acid has basicity $3$ where the number of replaceable ${{H}^{+}}$is three.


Therefore a tribasic acid is a citric acid.
Thus option (D) is the correct answer.

Note: Acidity of a base is equal to the number of $O{{H}^{-}}$ ions present in it or other words, the number of hydroxyl ions produces when one molecule of a base undergoes dissociation is called acidity of a base. $Ca{{(OH)}_{2}}$is an example of a diacid base as it gives two $H{{O}^{-}}$in an aqueous solution.