Verified Solution • 2025–26 Session
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QJEEAdv14Ch4eb6: JEE Advanced 2014 Chemistry - Class 12 JEEAdv14Ch4eb6 Solution: The correct statement(s) for orthoboric acid is/are
The correct statement(s) for orthoboric acid is/are
Multiple Choice Options
- A it behaves as a weak acid in water due to self ionisation
- B acidity of its aqueous solution increases upon addition of ethylene glycol
- C it has a three dimensional structure due to hydrogen bonding
- D it is a weak electrolyte in water
Step-by-Step Verified Solution
(a) It does not undergo self ionisation in water but accepts an electron pair from water, so it behaves as weak monobasic acid
H3BO3 + H2O B(OH) + H+
Hence, (a) is incorrect.
(b) When treated with 1, 2-dihydroxy or polyhydroxy compounds, they form chelate (ring complex) which effectively remove [B(OH)4] species from solution and thereby produce maximum number of H3O+ or H+ ions, i.e., results in increased acidity.
(c) Baric acid crystallises in a layer structure in which planar triangular BO ions are bonded together through hydrogen bonds.
(d) In water the pKa value of H3BO3 is 9.25
H3BO3 + H2O B(OH) + H+ ; pKa = 9.25
So, it is weak electrolyte in water.
H3BO3 + H2O B(OH) + H+
Hence, (a) is incorrect.
(b) When treated with 1, 2-dihydroxy or polyhydroxy compounds, they form chelate (ring complex) which effectively remove [B(OH)4] species from solution and thereby produce maximum number of H3O+ or H+ ions, i.e., results in increased acidity.
(c) Baric acid crystallises in a layer structure in which planar triangular BO ions are bonded together through hydrogen bonds.
(d) In water the pKa value of H3BO3 is 9.25
H3BO3 + H2O B(OH) + H+ ; pKa = 9.25
So, it is weak electrolyte in water.