Question

Substance A will not dissolve in water. What can be said about substance A?

Answer 1

Chemical compounds were classified into two types based on the movement of electrons between the atoms in the molecules. Polar compounds dissolve in polar solvents like water whereas non-polar compounds dissolve in non-polar solvents only. As like dissolves in like nature.

Complete answer:
Atoms are the tiny particles consisting of subatomic particles like electrons, protons, and neutrons. Atoms combine with each other and form molecules. If there is a large difference in the values of electronegativities in the atoms of the molecule, there will be a movement of electrons between the atoms leading to polarity.
Thus, polarity can be defined as the movement of electrons. water is a compound consisting of polar nature as water can easily dissociate into hydrogen ions and hydroxide ions.
From the statement like dissolves in like nature compounds, polar compounds dissolves in polar solvents like water. Whereas non-polar compounds like alkanes will not be soluble in water. Non-polar compounds mean there is a small difference of electronegativity between the two atoms.
Given that Substance A will not dissolve in water. It means substance A is non-polar and dissolves in non-polar solvents like kerosene or benzene.

Note:
If the two atoms in a molecule have the electronegativity difference more than $1.7$ , then the ionic compounds will be formed which will have the nature of polarity, when there is an electronegativity difference less than $1.7$ , covalent compounds which will have the nature of non-polarity.