... a = 1 ,2 ChnB Cõu 24 : Cho m gam X gm Fe, FeO, Fe3O4, Fe2O3 vo 400 ml dung dch HCl 2M, sau phn ng thu c 2, 24 lớt H2 (ktc), dung dch Y, v 2, 8 gam Fe khụng tan Giỏ tr m l: A 27 ,2 B 25 ,2 C 22 ,4 D ... 30,7 gam hn hp Na, K, Na2O, K2O tỏc dng vi dd HCl va thu c 2, 464 lớt H2 (ktc) v dung dch cha 22 ,23 gam NaCl v x gam KCl Giỏ tr ca x l: A 32, 78 B 35,76 C 34 ,27 D 31 ,29 22 ,23 BTNT.Na 0,38 = Na ... hyroxit kim loi M húa tr II khụng i vo dung dch H2SO4 nng 25 % va thu c dung dch mui cú nng 32, 65% Hyroxit kim loi ó dựng l A Cu(OH )2 B Pb(OH )2 C Mg(OH )2 D Zn(OH )2 Ta gi s cú mol M(OH )2 H2 SO...