第一类、放出气体或生成沉淀时的反应先后:1、向Na2CO3和NaOH的混合溶液中滴入稀HCl。稀HCl能与Na2CO3反应生成CO2气体,也能与NaOH发生中和反应,但实际反应时,NaOH先和HCl中和,等NaOH被反应完后,Na2CO3才能和HCl反应放出CO2气体。因为CO2会被NaOH溶液吸收。小结:溶液中有碱时,不可能从里面放出酸性气体(CO2、SO2、HCl等)2、向NH4Cl和HCl的混合溶液中滴入NaOH溶液。NaOH溶液能与NH4Cl反应生成NH3气体,也能和HCl发生中和...
M11.It’ssaidthatthisdiseaseaffectsmillionsintheworldeveryyear.(侵袭,使感染)2.Inthelastyears,Ihavereadvariousnews,whichisvitaltomyargument.(论点)3.Hi,wouldyoupleasegothroughthereportofchemicalcompositioninspection?(成分)Ok,I’mgladto.4.Inmyopinion,governmentofficialsclearlydeservesomeoftheblameaswellindealingwiththedisaster.(应受到)5.AfterdealingwithRose,hefoundhercold,ice-likeanddistant...