Question

Boric acid is prepared from borax by the action of
A. $ HCl $
B. $ NaOH $
C. $ C{O_2} $
D. $ N{a_2}C{O_3} $

Answer 1

Hint: Boric acid is an inorganic compound which is prepared by the reaction of borax with mineral acid which is hydrogen chloride. Boric acid is present in nature in the form of a mineral which is called sassolite. The chemical formula of borax is $ N{a_2}{B_4}{O_7} $ .

Complete answer:
Boric acid is prepared by the action of hydrogen chloride that is $ HCl $ on borax. Borax is called sodium tetraborate, it is white crystalline solid. When it is reacted with water and hydrogen chloride we get combination of neutral compound and weak acid as a product
 $ NaCl $ is neither a base or acid and $ {H_3}B{O_3} $ is a weak acid that is boric acid also called as orthoboric acid.
Following balanced reaction takes place:
 $ N{a_2}{B_4}{O_7} + 2HCl + 5{H_2}O \to 2NaCl + 4{H_3}B{O_3} $
The by-product in this reaction is sodium chloride.
This method is used to produce boric acid on a commercial scale.
The correct answer is A.

Note:
Boric acid can be also prepared with the help of hydrolysis of diborane and trihalides of boron. Boric acid is mainly used as antiseptic in pharmaceutical companies. It is also used as neutron poison in some nuclear plants.