Question

What is the solubility of methane, ethane and propane in water $?$

Answer 1

Hint: The solubility of solute in the solvent depends on the interaction between the solute and solvent. When the interaction between the solute and solvent is negligible then it is said to be insoluble. Therefore here we have to check the interaction of methane, ethane and propane with the water molecule.

Complete answer:
The solubility of a substance depends on the type of interaction it makes with the given solvent. We know that methane, ethane and propane, all are organic compounds. They are pure carbon chains which contain only carbon and hydrogen. Therefore they are non-polar in nature. On the other hand, we know that water is a polar molecule which contains hydrogen and oxygen. The attraction between atoms of water is dipole-dipole attraction. But on the other hand there is no such attraction between carbon and hydrogen in case of methane, ethane and propane. There is only the Vander wall force of attraction in case of hydrocarbons. Thus the given hydrocarbons are insoluble in the water. Also we know that like dissolves like which means that polar compounds are soluble in polar solvent only. Similarly non-polar compounds like methane, ethane and propane are soluble only in non-polar solvent. Therefore we can say that all these hydrocarbons are insoluble in water.

Note:
Methane, Ethane and propane are pure organic compounds which means that these compounds do not contain any functional group. If any polar functional group gets attached to these compounds then polar character develops in the compound which may make them soluble in the water. More the polar nature in the compound, the more soluble in water.