Short answers, pulled from the story.
Claude Louis Berthollet (the 9th of December 1748 - the 6th of November 1822) was a Savoyard-French chemist known for his contributions to chemical equilibrium theory, modern chemical nomenclature, and the development of chlorine-based bleaching agents. He also became vice president of the French Senate in 1804.
Eau de Javel is a weak solution of sodium hypochlorite that Berthollet first produced in 1789 at his laboratory on the quay Javel in Paris. He made it by passing chlorine gas through a solution of sodium carbonate, creating a liquid that became the basis of modern bleach.
Berthollet and Joseph Proust disagreed over the law of definite proportions, which holds that chemical compounds always combine in fixed elemental ratios. Proust was eventually vindicated when Berzelius confirmed his view in 1811, but a class of non-stoichiometric compounds that do not obey fixed proportions was later discovered and named berthollides in Berthollet's honor.
Berthollet co-authored the 1788 publication Methode de Nomenclature Chimique alongside Antoine Lavoisier, Louis Bernard Guyton de Morveau, and Antoine Francois, comte de Fourcroy. That work established the systematic naming conventions that form the basis of the modern system for naming chemical compounds, and received a Citation for Chemical Breakthrough Award from the American Chemical Society in 2015.
Yes. Berthollet was one of several scientists who accompanied Napoleon to Egypt and served as a member of the physics and natural history section of the Institut d'Egypte.
Berthollet's Salt is the informal name for potassium chlorate (KClO3), a strong chlorine oxidant and bleach that Berthollet was the first to investigate and produce.