Write a balanced chemical equation for each of the following reactions:

(i) Magnesium hydrogen carbonate reacts with slaked lime.

(ii) Formation of coloured precipitate.

(iii) Heating ammonium dichromate.

(i) Magnesium hydrogen carbonate reacts with slaked lime.

Mg(HCO₃)₂ + Ca(OH)₂ ⟶ MgCO₃↓ + CaCO₃↓ + 2H₂O

(ii) Formation of coloured precipitate.

3NaOH + FeCl₃ ⟶ Fe(OH)₃ [reddish brown ppt.] + 3NaCl

(iii) Heating ammonium dichromate.

$\underset{\text{[Ammonium dichromate (orange)]}}{(\text{NH}$4)2\text{Cr}2\text{O}7} \xrightarrow{\space \Delta \space} \underset{\text{ [Chromic oxide(green)]}}{\text{Cr}2\text{O}3} + 4\text{H}2\text{O} + \text{N}2