<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31320409</termId><termName>alkali</termName><termType>PT</termType><termNote><![CDATA[ Compounds having highly basic properties, specifically any of the soluble hydroxides of the alkali metals; a general term now used for any basic material (pH greater than 7). In general, alkali compounds will react with fatty acids to form soaps; turn litmus paper blue; dissolve in water to form alkaline solutions; taste bitter and are irritating to the skin. Alkaline solutions are used in deacidifying and buffering paper. Alkalis also act as fluxes in ceramics and glass production.  ]]></termNote><termCreatedDate>2026-03-30 20:26:21</termCreatedDate><relation><relationType>BT</relationType><termId>31306099</termId><termName>base</termName><termType>PT</termType></relation><relation><relationType>RT</relationType><termId>31301249</termId><termName>alkalinity</termName><termType>PT</termType></relation><relation><relationType>RT</relationType><termId>31306060</termId><termName>acid</termName><termType>PT</termType></relation></term>  </Zthes>