Question

This chemical reaction I wrote on a blackboard when the teacher is going to conduct an experiment on chemical equilibrium. In the belowreaction which reaction has red color?
$Fe{\left( {N{O_3}} \right)_3} + 3KCNS \to Fe{\left( {CNS} \right)_3} + 3KN{O_3}$

Answer 1

Hint: An equilibrium reaction is the one in which the forward and reverse reactions are the same. Or you can say that the rate for forward reaction is the same as the rate for backward reaction depending upon the experimental conditions. The process is reversible which means the products and reactants can be reversed.

Complete answer:
We must have to know that equilibrium can be studied by looking at an example i.e. dissociation of water is a reversible process that means equilibrium lies when water dissociates into ions.
When ferric nitrate reacts with potassium thiocyanate solution it gives potassium nitrate and ferric thiocyanate. This reaction is taking place in equilibrium as said in the question. The compound which is red in color is ferric thiocyanate, the intensity of this solution will depend upon the complex’s amount in a chemical reaction. The reactants will combine forming the products until an equilibrium state is reached on moving a forward direction and same when the product starts decomposing into reactants until the equilibrium is attained on moving backward direction. Ferric nitrate solution is yellow in color whereas potassium thiocyanate is colorless and the forming product that is ferric thiocyanate is red in color.
Thus the best way to represent this chemical equation is shown below:
$Fe{\left( {N{O_3}} \right)_3} + 3KCNS \to Fe{\left( {CNS} \right)_3} + 3KN{O_3}$

Note:
We have to remember that the color observed when ferric nitrate and potassium thiocyanate is mixed is red color, when more potassium thiocyanate is added the color becomes redder and when the solution is placed in a ice bath it becomes orange and after placing in hot bath it turns yellow. That’s how this experiment works.