The answer is 67 108.0888km/s.
Soap has both a polar end and a nonpolar end. Thus, it maybe soluble to most of the substances. It exhibits both properties of non-polar and polar molecules. The hydrocarbon chain is the non-polar side while the salt end is the polar end.
There are three ways that scientists have proved that these sub-atomic particles exist. They are direct observation, indirect observation or inferred presence and predictions from theory or conjecture. Scientists in the 1800's were able to infer a lot about the sub-atomic world from chemistry.