The organic compund that is the least likely to be used as an organic solvent is:
aldehyde
Explanation:
The reason behind this is that even though aldehydes are used in the perfumery industry. They are not very good solvents because the majority of them are hazardous. Only a minimal fraction of them can be tolerated by organisms and that can even make them have weak poisoning reactions. However, using them as solvents in bigger quantities will make them hazardous for organisms considering their high concentration of ketones.
