Question

What is an insoluble substance?

Answer 1

Hint :We know that Insoluble salts are those ionic compounds that are not able to dissolve in water but form a suspension, i.e., the salt continues to exist as a solid rather than dissolving in liquid. As polar and nonpolar substances are insoluble when mixed with each other.

Complete Step By Step Answer:
Insoluble salts are those ionic compounds that are not able to dissolve in water but form a suspension, i.e., the salt continues to exist as a solid rather than dissolving in liquid. As polar and nonpolar substances are insoluble when mixed with each other.
"Insoluble" generally means that a substance does not dissolve in water. Some examples include: sand, fats, wood, metals, and plastic. When we put them in water and try to mix them, they will not dissolve.
An example of an insoluble substance is sand (quartz) in water. Thus, sand can be separated from the water by filtration, or/and sedimentation. On the other hand soluble substance can be Silicon fluoride, on reacting sand ( $Si{O}_2$ ) with hydrofluoric ( $HF$ ) acid, according to the following reaction:
 $Si{O}_2+HF\to Si{\left(F\right)}_2+H_{2}O$
According to the above chemical reaction, the product of Silicon fluoride " $Si{\left(F\right)}_2$ " is soluble in the hydrofluoric acid media.

Note :
Don’t get confused in the elements and the compounds. Elements are those substances which are made up of only one type of particles or the substances. Elements consist of both atoms and the molecules. Atoms are made up of only one type of particle.