# Double Replacement Reactions: Complete and balance. Identify the precipitate (highlight it!!)?

May 24, 2017

In aqueous solution we would expect ionization of the individual reagents.......

#### Explanation:

$\left(i\right)$ $A {g}^{+} + C {l}^{-} \rightarrow A g C l \left(s\right) \downarrow$

$A g C l$ is as soluble as a brick. The state is indicated by $\left(s\right)$, i.e. $\text{solid}$; some chemists put a down arrow as shown to emphasize its precipitation.

ELSE,

$2 A g N {O}_{3} \left(a q\right) + M g C {l}_{2} \left(a q\right) \rightarrow 2 A g C l \left(s\right) \downarrow + M g {\left(N {O}_{3}\right)}_{2} \left(a q\right)$

The magnesium ions, and the nitrate ions are thus along for the ride and do not participate in MACROSCOPIC chemical change.

$\left(i i\right)$ $F {e}^{2 +} + H {O}^{-} \rightarrow F e {\left(O H\right)}_{2} \left(s\right) \downarrow$

ELSE,

$F e C {l}_{2} \left(a q\right) + 2 N a O H \left(a q\right) \rightarrow F e {\left(O H\right)}_{2} \left(s\right) \downarrow + 2 N a C l \left(a q\right)$

The sodium ions, and the chloride ions are thus along for the ride and do not participate in MACROSCOPIC chemical change.

$\left(i i i\right)$ $C {O}_{3} {\left(a q\right)}^{2 -} + F {e}^{2 +} \rightarrow F e C {O}_{3} \left(s\right) \downarrow$

ELSE,

$N {a}_{2} C {O}_{3} \left(s\right) + F e S {O}_{4} \left(a q\right) \rightarrow 2 F e C {O}_{3} \left(s\right) \downarrow + N {a}_{2} \left(S {O}_{4}\right) \left(a q\right)$

Upon dissolution of the salts in an aqueous medium; SOME of the ions are spectator ions and thus do not participate in reaction. The given net ionic equations reflect the macroscopic chemical change.