Tiến hành các thí nghiệm sau: (1) Hòa tan Fe2O3 bằng lượng dư dd HCl

* Hướng dẫn giải

Chọn C

(1)${\mathrm{Fe}}_2{\mathrm{O}}_3+6{\mathrm{H}}^{+}\to 2{\mathrm{Fe}}^{3+}+3{\mathrm{H}}_2\mathrm{O}$

$16{\mathrm{H}}^{+}+10{\mathrm{Cl}}^{-}+2{{\mathrm{MnO}}_4}^{-}\to 2{\mathrm{Mn}}^{2+}+5{\mathrm{Cl}}_2\uparrow +8{\mathrm{H}}_2\mathrm{O}$

(2)${\mathrm{K}}_2{\mathrm{S}}_2{\mathrm{O}}_3+{\mathrm{H}}_2{\mathrm{SO}}_4\to \mathrm{S}+{\mathrm{SO}}_2+{\mathrm{K}}_2{\mathrm{SO}}_4+{\mathrm{H}}_2\mathrm{O}$

(3)${\mathrm{MnO}}_2+4\mathrm{HCl}\to {\mathrm{MnCl}}_2+{\mathrm{Cl}}_2+2{\mathrm{H}}_2\mathrm{O}$

(4)$2{\mathrm{KNO}}_3+\mathrm{S}+3\mathrm{C}\to {\mathrm{K}}_2\mathrm{S}+{\mathrm{N}}_2+3{\mathrm{CO}}_2$

(5)${\mathrm{O}}_3+2\mathrm{Ag}\to {\mathrm{Ag}}_2\mathrm{O}+{\mathrm{O}}_2$

(6)${\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{loãng}\right)+\mathrm{NaBr}\left(\mathrm{khan}\right)\to \mathrm{không} \mathrm{xảy} \mathrm{ra} \mathrm{phản} \mathrm{ứng}$(7)$2{\mathrm{KClO}}_3+{\mathrm{SO}}_2\to {\mathrm{Na}}_2{\mathrm{SO}}_3+{\mathrm{SO}}_2$

(8)${\mathrm{Na}}_2{\mathrm{CO}}_3+{\mathrm{SO}}_2\to {\mathrm{Na}}_2{\mathrm{SO}}_3+{\mathrm{SO}}_2$