... thu c cht C cú c ng thc phõn t lC4H6O2 . C ng thccu to ca C l:A. CH2 =C( CH3)-COOH B. CH2=CH-CH2-COOH C. CH2-CH=CH-COOH D. CH2=CH-COO- CH3 C u 47: in li ca 3 dung dch CH3COOH ... NH4Cl, N2 B. N2 ,NH3 , HCl C. NH3 , HCl , NO2 D. NH3 , HCl , NO C u16: Cho c c cht : CH2=CH-COOCH3 ; CH2=CH-CHO ; CH3COOCH=CH2; CH3-CH(OH)-COOH;CH2=CH-CH3.S cht c ... HO-CH2-CH2-CH=CH-CHO C. HO-CH2-CH=CH-CHO D. HO-CH2-CH2-CH2-CHO C u 43: Cho c c cht :Cr2O3, Al2O3 , Cr(OH)3 , AlCl3, Al, Cr , (NH4)2CO3,CrO3 ,CrO, Cr(OH)2 . s cht...