Question

$B{{F}_{3}}$ on hydrolysis forms
a) ${{H}_{3}}B{{O}_{3}}$
b) $HB{{F}_{4}}$
c) both a) and b)
d) None of these

Answer 1

Hint: Hydrolysis basically means treatment of chemical compounds with water. Since $B{{F}_{3}}$is a Lewis acid , it reacts with water to give acid. This point leads to the correct answer.
Complete step by step solution:
$B{{F}_{3}}$ is an inorganic compound and is toxic gas which forms white fumes in moist air. It has a pungent smell and is very useful Lewis acid and acts as a building block for other boron compounds.
-Since boron trifluoride is not available directly, it is synthesized in situ on reaction of boron oxides with hydrogen fluorides.
-Boron trifluoride is soluble in water and slowly hydrolyzed by cold water to give the desired products.
-boron trifluoride on the other hand is stable because of the fact that energy is being lost from the system .
-Therefore, the hydrolysis reaction of boron trifluoride gives boric acid and fluoro boric acid respectively.
The reaction is as shown below,
\[4B{{F}_{3}}+3{{H}_{2}}O\to {{H}_{3}}B{{O}_{3}}+3HB{{F}_{4}}\]

Therefore, the correct answer is option c).

Additional information:
-Interesting fact about boron trifluoride is that it does not form ionic bonds with fluorine. Thus it is because the total energy required for removing three electrons to form boron (+3) ion is very much higher to be recoverable. Thus, strong attractions are set up between the boron and trifluoride ion which makes it more stable.

Note: The acid hydrolysis process always yields two components in which one picks up a proton to yield another acid. This fact helps you to easily understand hydrolysis reactions for acid.