Question

For each solute, identify the better solvent: water or carbon tetrachloride. Water, H2O Carbon tetrachloride, CCl4

Answer 1

Concepts and reason

The concept of “like dissolves like” is used in the question. It means that polar solutes readily dissolve in the polar solvent whereas non-polar solutes dissolve easily in non-polar solvent.

Fundamentals

Electronegativity: The tendency of an atom to attract a shared pair of electron towards itself is known as electronegativity.

Polar compounds: If the atoms of the compound have a significant electronegativity difference, then the electron cloud shifts towards the more electronegative atom developing a partial negative charge on itself and a partial positive charge on the other atom. Such compounds are called polar compounds. Example, hydrochloric acid.

Non-Polar compounds: If the compounds do not have much significant difference in their electronegativity, then they are held together by sharing of electrons. Such compounds are called non-polar compounds. Example, benzene.

Two solvents are given as ${{\rm{H}}_{\rm{2}}}{\rm{O}}$ and ${\rm{CC}}{{\rm{l}}_{\rm{4}}}$ . Both show different properties due to the difference in the electronegativity between their atoms.

Hence, ${{\rm{H}}_{\rm{2}}}{\rm{O}}$ is a polar molecule and ${\rm{CC}}{{\rm{l}}_{\rm{4}}}$ is a non-polar molecule.

• ${\rm{KF}}$ and ${\rm{N}}{{\rm{H}}_{\rm{3}}}$ is a polar molecule.

${{\rm{C}}_{\rm{6}}}{{\rm{H}}_{{\rm{14}}}}{\rm{,}}\;{\rm{and}}\;{{\rm{I}}_{\rm{2}}}$ are non-polar molecules.

• Therefore, best solvent for ${\rm{KF}}$ and ${\rm{N}}{{\rm{H}}_{\rm{3}}}$ is ${{\rm{H}}_{\rm{2}}}{\rm{O}}$ .

And for ${{\rm{C}}_{\rm{6}}}{{\rm{H}}_{{\rm{14}}}}{\rm{,}}\;{\rm{and}}\;{{\rm{I}}_{\rm{2}}}$ , the best solvent is ${\rm{CC}}{{\rm{l}}_{\rm{4}}}$ .

Ans:

The table showing the solvent which is better for each solvent is as follows: