Orthoboric Acid - Practice Questions & MCQ

Orthoboric acid, H₃BO₃ is a white crystalline solid, with soapy touch. It is sparingly soluble in water but highly soluble in hot water. It can be prepared by acidifying an aqueous solution of borax.

It is also formed by the hydrolysis (reaction with water or dilute acid) of most boron compounds (halides, hydrides, etc.). It has a layer structure in which planar BO₃ units are joined by hydrogen bonds as shown in the figure given below. 
Boric acid is a weak monobasic acid. It is not a protonic acid but acts as a Lewis acid by accepting electrons from a hydroxyl ion:

On heating, orthoboric acid above 370K forms metaboric acid, which on further heating yields boric oxide, .