Phương pháp giải:

Lời giải chi tiết:

Phương trình hóa học 

$\eqalign{ & \mathop {Na}\limits^{ + 1} \mathop {Cl}\limits^{ - 1} + \mathop {Ag}\limits^{ + 1} \mathop N\limits^{ + 5} {\mathop O\limits^{ - 2} _3} \to \mathop {Ag}\limits^{ + 1} \mathop {Cl}\limits^{ - 1} + \mathop {Na}\limits^{ + 1} \mathop N\limits^{ + 5} {\mathop O\limits^{ - 2} _3} \cr & \mathop {Fe}\limits^0 + {\mathop {Cl}\limits^0 _2} \to \mathop {Fe}\limits^{ + 3} \mathop {C{l_3}}\limits^{ - 1} \cr & \mathop {Zn}\limits^0 + {\mathop H\limits^{ + 1} _2}\mathop S\limits^{ + 6} {\mathop O\limits^{ - 2} _4} \to \mathop {Zn}\limits^{ + 2} \mathop S\limits^{ + 6} {\mathop O\limits^{ - 2} _4} + {\mathop H\limits^0 _2} \cr & \mathop K\limits^{ + 1} \mathop {Mn}\limits^{ + 7} {\mathop O\limits^{ - 2} _4}\buildrel {{t^o}} \over \longrightarrow {\mathop K\limits^{ + 1} _2}\mathop {Mn}\limits^{ + 6} {\mathop O\limits^{ - 2} _4} + \mathop {Mn}\limits^{ + 4} {\mathop O\limits^{ - 2} _2} + {\mathop O\limits^0 _2} \cr}$

Đáp án A