Question: Which Class IB flammable liquid has the least lower flammable limit?
Paraphrase: What flammable liquid has the least lower flammable limit in Class IB?
SPARQL (Wikidata): select ?ent where { ?ent wdt:P31 wd:Q21009055 . ?ent wdt:P2202 ?obj } ORDER BY DESC(?obj)LIMIT 5 
Answer: bromoethane, 1,2-dichloroethane, methanol, (1E)-1,2-dichloroethylene, ethylidene chloride