Solveeit Logo
Login

Question

Question: Which of the following is not a protonic acid? A.\(PO{{(OH)}_{3}}\) B.\(B{{(OH)}_{3}}\) C.\(SO...

Which of the following is not a protonic acid?
A.PO(OH)3PO{{(OH)}_{3}}
B.B(OH)3B{{(OH)}_{3}}
C.SO(OH)3SO{{(OH)}_{3}}
D.SO2(OH)2S{{O}_{2}}{{(OH)}_{2}}

Explanation

Solution

It is to be recalled that an acid is said to be protonic only if the acid releases H+{{H}^{+}} ion in its aqueous solution. Substances which have excess or deficiency of electrons are called Lewis acids or bases.

Complete answer:
In order to answer our question, we need to learn about the Lewis acids and bases. Both the Arrhenius and Bronsted Lowry concepts are limited to the substances which contain hydrogen and give protons. G.N. Lewis gave a new concept in 1923 which eliminated the necessity of a proton, As a result many more substances could be named as acids and bases according to this concept. The acid and base can be defined as "Acid is a substance which can accept a pair of electrons while base is a substance which can donate a pair of electrons". This concept is also called electronic concept according to which a Lewis base donates an electron pair to be accepted by a Lewis acid. The two get linked to each other by coordinate bonds. However, there are some limitations to the Lewis concept. They are:
i.It fails to assign the strength of acids and bases.
ii. According to this concept, the acid base reactions should be accompanied by the formation of dative bonds, but no such bonds are formed when acids like HCL, H2SO4{{H}_{2}}S{{O}_{4}}, HNO3HN{{O}_{3}}, etc. react with NaOH or KOH.
iii.Acid-base reactions are usually fast but the formation of dative bonds is a slow process.
iv. Catalytic property of the acids is due to H ions furnished by them. But the Lewis concept does not permit any such property.
Now let us come to our question. Boric acid is a Lewis acid, as it accepts electron pairs from suitable Lewis base. It doesn't release hydronium ions in aqueous solution.

So our correct answer is option B. B(OH)3B{{(OH)}_{3}}.

NOTE: The Bronsted-Lowry concept and Lewis concepts have a broader base than the Arrhenius concept. But the Arrhenius concept is the most acceptable because many phenomena relating to acids and bases can be explained mainly by this concept.