A \( H g_{2}{I}_{4} + 2 N H_{3} = N H_{2} \left [ H g_{2}{I}_{3} \right ] + N H_{4} I \)
B \( 2 C u S O_{4} + 2 N H_{4} O H = C u S O_{4} . C u \left ( O H \right )_{2} + \left ( N H_{4} \right )_{2} S O_{4} \)
C \( F e C l_{3} + 3 N H_{4} O H = F e \left ( O H \right )_{3} + 3 N H_{4} C l \)
D \( 2 K I + H g{C} l_{2} = 2 K C l + H g{I}_{2} \)