31Vulcanisation of rubber uses:ACarbonBChlorineCZincDSulphurView AnswerDiscussWorkspaceReportSaveEasy
32Which gas is used in filling electric bulbs?AArgonBCarbon dioxideCOxygenDHydrogenView AnswerDiscussWorkspaceReportSaveEasy
33Lemons are sour because they contain:AFormic acidBTartaric acid onlyCCitric acidDAcetic acidView AnswerDiscussWorkspaceReportSaveEasy