<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31306060</termId><termName>acid</termName><termType>PT</termType><termNote><![CDATA[ Large class of electrolytic chemical substances that are capable of donating a hydrogen atom. Acids are classified as strong or weak depending on the concentration of hydrogen ion produced on ionization.  Acids exhibit one or more of the following characteristics: has a sour or sharp taste; forms an aqueous solution with a pH of less than 7.0; turns litmus dye red; reacts with bases and some metals to form salts; or reacts with a metal carbonate to release carbon dioxide.  ]]></termNote><termCreatedDate>2026-03-30 20:22:21</termCreatedDate><relation><relationType>UF</relationType><termId>31306061</termId><termName>acids</termName><termType>ND</termType></relation><relation><relationType>BT</relationType><termId>31298940</termId><termName>materials by property</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320277</termId><termName>acetic acid</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320280</termId><termName>carbolic acid</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320283</termId><termName>fatty acid</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320287</termId><termName>hydrochloric acid</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320293</termId><termName>hydrofluoric acid</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320295</termId><termName>nitric acid</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320297</termId><termName>sulfuric acid</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320304</termId><termName>phosphoric acid</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320308</termId><termName>tannin</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320312</termId><termName>pickle</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320313</termId><termName>boric acid</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320315</termId><termName>citric acid</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320316</termId><termName>amino acid</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320319</termId><termName>oxalic acid</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320321</termId><termName>formic acid</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320323</termId><termName>nucleic acid</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320233</termId><termName>alpha-lipoic acid</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320326</termId><termName>acrylic acid</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320328</termId><termName>silicic acid</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320331</termId><termName>lactic acid</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320335</termId><termName>carminic acid</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320338</termId><termName>uronic acid</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320341</termId><termName>gallic acid</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320349</termId><termName>hydrogen fluoride</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320343</termId><termName>adipic acid</termName><termType>PT</termType></relation><relation><relationType>NT</relationType><termId>31320347</termId><termName>phytic acid</termName><termType>PT</termType></relation><relation><relationType>RT</relationType><termId>31301243</termId><termName>acidity</termName><termType>PT</termType></relation><relation><relationType>RT</relationType><termId>31301245</termId><termName>acid resistance</termName><termType>PT</termType></relation><relation><relationType>RT</relationType><termId>31301257</termId><termName>acid-free</termName><termType>PT</termType></relation><relation><relationType>RT</relationType><termId>31320409</termId><termName>alkali</termName><termType>PT</termType></relation></term>  </Zthes>