Question

The substance as hard as diamond is:
(A) $ {B_3}{N_3}{H_6} $
(B) $ {B_2}{H_2} $
(C) $ {(BN)_n} $
(D) $ N{a_2}{B_4}{O_7} $

Answer 1

Hint : To answer this question, we first need to understand what is substance. A chemical substance is a type of stuff with a predictable chemical makeup and behaviour. Physical separation procedures, i.e., breaking chemical bonds, cannot separate a chemical substance into its constituent elements, according to some references.

Complete Step By Step Answer:
Diamond - Because diamonds are made of carbon, they develop as carbon atoms at high temperatures and pressures, bonding together to form crystals. Each carbon atom participates in four of these incredibly strong covalent bonds that form between carbon atoms, which is why a diamond is such a hard substance.
 $ {B_3}{N_3}{H_6} $ - Borazole is a polar inorganic chemical that is also known as borazine. The three BH units and three NH units alternate in this cyclic molecule. With benzene, the chemical is isoelectronic and structurally identical. Borazine is sometimes referred to as "inorganic benzene" because of this.
 $ {(BN)_n} $ - Boron nitride (BN) is a thermally and chemically resistant boron-nitrogen refractory compound having the chemical formula BN. It appears in a variety of crystalline forms that are isoelectronic to a carbon lattice with a comparable structure. Among the BN polymorphs, the hexagonal form corresponding to graphite is the most stable and soft, and is hence utilised as a lubricant and cosmetic component. C-BN is a cubic (sphalerite structure) variation similar to diamond with improved thermal and chemical stability. The BN alteration of wurtzite is similar to lonsdaleite.
 $ N{a_2}{B_4}{O_7} $ - Borax is a boron compound, a mineral, and a salt of boric acid. It is also known as sodium borate, sodium tetraborate, or disodium tetraborate. Borax powder is a white powder made up of soft colourless crystals that dissolve in water.
Boron Nitride Cubes The cubic form of boron nitride has a tetrahedral bond network formed by alternately connected boron and nitrogen atoms, just like carbon atoms in diamond.
So we conclude that $ {(BN)_n} $ is a material which is as hard as diamond.
So the final answer is option (C) i.e. $ {(BN)_n} $ .

Note :
One of the most well-known and sought-after jewels is the diamond. Since ancient times, they have been used as decorative ornaments. Diamond's hardness and great light dispersion, which gives it its distinctive "fire," make it suitable for industrial uses and desired as jewellery.