... hu c X hoc Y u thu c 1, 32 gam CO v 0 ,27 gam H2O, d X Y =3 Cụng thc phõn t ca X v Y ln lt l A C8H8 v C2H2 B C2H2 v C6H6 C C6H6 v C2H2 D C4H4 v C2H2 Cõu 18: Ho tan hon ton 20 ,9 gam hn hp gm Mg, ... COOH Cõu 21 : Thuc th nht phõn bit dung dch MgCl2, Na2CO3, Na2SiO3 l A dung dch NaOH B dung dch HCl C dung dch KNO3 D dung dch KCl Cõu 22 : Cho bt Zn vo dung dch hn hp Cu(NO 3 )2, Mg(NO3 )2 , kt thỳc ... c A Mg(OH )2 B Mg(OH )2, Cu(OH )2 C Mg(OH )2, Zn(OH )2 D Zn(OH )2 Cõu 23 : Cho cỏc cht sau: C H OH, C H , C H NH , C H 5ONa Chn mt thuc th nhn bit cỏc cht l A dung dch NaOH B dung dch BaCl2 C dung...