C2H5Br+NaOH→C2H4+NaBr+H2O条件醇溶液、加热C2H4+Br2→CH2Br-CH2Br  CH2BrCH2Br+2NaOH→2NaBr+HC≡CH+2H2O条件醇溶液、加热HC≡CH+HCL→CH2=CHCLnCH2=CHCL→[ ―CH2 ―CHCl― ]n（横线要穿过括号）...