Question

Which of the following is not an application of orthoboric acid?
A.As an antiseptic and eye wash
B.In glass industry
C.In glazes for pottery
D.In borax-bead test

Answer 1

Orthoboric acid tends to be a very weak acid. It can be used as can be used as an antiseptic, flame retardant, insecticide, neutron absorber and also as a precursor for other various chemical compounds

Complete step by step answer:
Orthoboric acid also known as aecidium barium, hydrogen borate, boracic acid and boric acid is a white crystalline solid which has a softy soapy touch and has a low density of $1.48g{m^3}$ . It is slightly soluble in cold water but is absolutely most soluble in hot water. Boric acid is a very weak acid. It is a monobasic Lewis acid of boron which can be used as an antiseptic, flame retardant, insecticide, neutron absorber and also as a precursor for other various chemical compounds. Boric acid is also called hydrogen borate. Orthoboric Acid is used for manufacturing of the heat resistant boron silicate glasses because of its structure. It is also used as a preservative for milk and many foodstuffs. It is also used to manufacture enamel.
When borax is heated, borax goes into a lot of variation and transition. It loses the water in it and also the water molecules and then swell ups. It is then transferred into a very transparent kind of liquid and then starts to solidify and form a glass kind of material which is known as borax bead. When boric acid is added to the water, it takes electrons or accepts from $- OH$ ions. Borax when heated gives ${B_2}{O_3}$ and $NaB{O_2}$ which is glass like structure or mass and is used for borax bead test. Borax bead test is performed only for salts which are colored.

Therefore, the correct answer is option (D).

Note: Boric Acid is not tribasic acid. When boric acid is strongly heated it loses water already present inside it and starts to swell into white mass and gives ${B_2}{O_3}$ and $NaB{O_2}$ which is Boric anhydride and sodium metaborate simultaneously.