Question

What happens when ammonium thiocyanate is added to ferric chloride.

Answer 1

We need to know that ammonium thiocyanate is an inorganic salt having chemical formula $N{H_4}SCN$. This salt is formed by combining ammonium cation and thiocyanate anion. Ferric chloride is an inorganic salt formed by joining ferric ions and chloride ions.

Complete answer:
Let’s see what happens when ammonium thiocyanate is added to ferric chloride, since $N{H_4}SCN$ is weakly acidic due to the ammonium ion; it reacts with alkali hydroxides, such as sodium hydroxide or potassium hydroxide to form sodium thiocyanate or potassium thiocyanate, along with water and ammonia. The thiocyanate anion, specifically, reacts with ferric salts to form a deep-red ferric thiocyanate complex. So when ammonium thiocyanate reacts with ferric chloride it forms a dark deep red color ferric thiocyanate complex.
$FeC{l_3} + N{H_4}SCN \to {\left[ {Fe\left( {SCN} \right)6} \right]^{3 - }} + N{H_4}^ +$
With this reaction iron (III) thiocyanate compound is formed. Ferric chloride is an orange to black brown solid. Ammonium thiocyanate is used in chemical analysis, in photography, as a fertilizer, and for many other uses. It can release ammonia vapors if mixed with a chemical base or with an acid.

Note:
We need to know that the primary use of ferric chloride is to remove impurities in water and for wastewater treatment. Ferric chloride is also one of the few water treatment chemicals that can sequester odors. The common oxidation of iron can be $+ 3$ oxidation state. The anhydrous compound is a crystalline solid with a melting point of $307.6^\circ C$. The color depends on the viewing angle: by reflected light the crystals appear dark green, but by transmitted light they appear purple-red.