Question

As compared to covalent compounds, electrovalent compounds generally have
A. Low melting points and low boiling points
B. Low melting points and high boiling points
C. High melting points and low boiling points
D. High melting points and high boiling points

Answer 1

Hint: The value of the boiling and melting point of a compound gives the value of the temperature at which the compound starts boiling and starts melting respectively.
If the bond strength is high, it will be difficult to break the bond, and B.P or M.P will be higher.

Complete step-by-step solution:Ionic or electrovalent bond makes the atoms involved gain and lose the valence electrons.
It is mainly formed by metal and nonmetal.
The metal removes electrons forming a positively charged cation, whereas the nonmetal gets those electrons forming a negatively charged anion.
A bond strength gives us information about how firmly atoms are bound to each other, and thus the amount of energy needed to break the bond.
The covalent compound has less bond strength than the ionic compound.
An ionic compound is stable due to electrostatic attraction between the oppositely charged ions.
The lattice energy of a compound is an estimation of the stability of this attraction.
The lattice energy is the energy necessary to break down one mole of the solid into its gaseous ions.
The ionic compounds have high lattice energy so it becomes difficult to break the bond.
So, a high amount of energy is demanded to break the bond.
So, electrovalent compounds generally hold
increased melting points and increased boiling points.

So, option D is correct

Note: We see stable molecules around us as covalent bonds grip the atoms together, isolating any pair of bonded atoms needs energy. The energy needed to break one mole of the covalent bond of gaseous molecules is the bond energy or the bond dissociation energy.