Mescalero-Chiricahua Apache is a family of languages that is spoken in Oklahoma and New Mexico. The Oklahoma language is in dire need of assistance; while most Indigenous languages in North America are in danger of extinction, this one has as few as three native speakers remaining.
Basic problems with corrosive chemicals... Corrosive: A chemical, (solid, liquid or gas), that can cause destructive damage to body tissues at the site of contact. It can cause severe burns to the skin and can eat through clothing, metal and other materials.
The term caustic can also mean corrosive.. This type of brake fluid can be corrosive to some paints, chromes, and plastics. It also can cause irritation when exposed to skin, and is toxic if ingested. I suspect this is why brake fluid is labeled as caustic. Regarding your question about pH: it doesn't apply. pH is a measure of the H+ ions in an aqueous (water) solution. The lower the pH, the greater the content of H+ ions in the water, and the more acidic it is.