KHC8H4O4 is potassium hydrogen phthalate. The word 'hydrogen' is referring the the acidic hydrogen. This hydrogen comes off to neutralize the any OH- ions. In the image below a potassium ion has replaced a hydrogen. Before the hydrogen was replaced, the molecule was called phthalic acid. chemistryland.comBy DAVID JOLLY
7 January 2013

PARIS (The New York Times) – About five years ago, Alain Lenoir, a researcher at François Rabelais University in Tours, France, was studying the biochemical process by which ants differentiate between friends and foes. Scientists had come to understand that the insects used their antennae to sense the makeup of the hydrocarbons of other ants’ cuticles. Using chemical analyses like gas chromatography, Dr. Lenoir had begun focusing in particular on hydrocarbons on Lasius niger, the common black ant. Dr. Lenoir, who has been studying ants since 1968, found something unexpected: in addition to the hydrocarbons, the analysis was consistently revealing the presence of plastic additives called phthalates, and not just in a few specimens – all of them. Other scientists had reported such findings, he said, but he had brushed off the presence of those chemicals as contamination that occurred in the lab. Intrigued, Dr. Lenoir, today an emeritus professor, decided to follow up with a new study. The results, published in last month’s issue of Science of the Total Environment, an academic journal, confirmed what he had already come to fear. All of the ants that he and his team studied were contaminated with phthalates, regardless of where the insects originated. For example, the chemical made up as much as 0.59 percent of the substances on the cuticles of ants that had just been collected in a field near Tours. […] Phthalates are thought to be endocrine disruptors, chemicals that alter the way animal hormones operate. Phthalates are not bound chemically to the plastics to which they are added and enter the environment naturally as the plastic deteriorates with age. […] “Phthlates are everywhere in the atmosphere,” Dr. Lenoir said in an interview. Some of the contamination of the ants in the open boxes certainly must have come from other plastics in the laboratory, he added, though that would have also been the case in people’s houses, where plastics are everywhere. […] And it wasn’t just the ants, the French researchers found. They also tested wood crickets and honeybees, with the same result. [more]

Ant Study Deepens Concern About Plastic Additives