Question

Which of the following solid has maximum melting point?
A) $$\text{NaCl}$$
B) Ice
C) Dry ice
D) $$\text{Si}{\text{O}}_{\text{2}}$$

Answer 1

Hint: In matters are divided into three types. There are solids, liquids and gas. Solids are divided into types. They are crystalline and amorphous. The crystalline is further divided into ionic solids, covalent solids, molecular solids and metallic solids. In crystalline solid, the basic repeating structural unit is called a unit cell.
In chemistry molecules are made up of bonds only. There are three types of bond in the chemical bond. There are ionic bonds, covalent bonds and coordinate bonds.

Complete answer:
We must have to know that the covalent bond is nothing but the mutual sharing of electrons between the two atoms in the molecule.
The ionic bond means one atom donates the electron and another accepts the electron in the molecule.
Hydrogen bond also one of the important bonds in chemistry. Without hydrogen bond nothing in the world. There are two types of hydrogen bond. There are intermolecular hydrogen bond and intramolecular hydrogen bond. The hydrogen bond is depend on the most electronegativity atom in the molecule.
The given solids are $$\text{NaCl}$$, Ice, Dry ice and $$\text{Si}{\text{O}}_{\text{2}}$$.
The molecular formula of sodium chloride is $$\text{NaCl}$$. It is due to ionic bond.
The molecular formula of Ice is $${\text{H}}_{\text{2}}\text{O}$$. It is due to intermolecular hydrogen bond.
The molecular formula of Dry ice is $$\text{C}{\text{O}}_{\text{2}}$$. It is due to Van Der Waals force.
The molecular formula of silicon dioxide is $$\text{Si}{\text{O}}_{\text{2}}$$. It is due to covalent bond.
Silicon dioxide solid has the maximum melting point in the given list. Because silicon dioxide has a strong covalent bond.
According to the above discussion, we conclude $$\text{Si}{\text{O}}_{\text{2}}$$ solid has a maximum melting point.

Hence, the option D is the correct answer.

Note:
There are seven types of primitive crystal system. There are cubic, tetragonal, orthorhombic, hexagonal, monoclinic, triclinic and rhombohedral. This classification of crystal is based on the crystallographic nature of angles, unit cell, primitive lattice and axes. These cubic crystals are further divided into three types. There are simple cubic crystals, face centered cubic crystal and body centered cubic crystal. This classification is based on the atoms arrangement in the cubic structure in the unit cell.