Question

Refer to the equilibrium below to answer the question. FeCl3 + 6 KSCN – K3[Fe(SCN)6] + 3 KCI yellow colorless red colorless Adding a couple of drops of an aqueous KCl solution will turn the solution less red. have no effect on the color turn the solution clear turn the solution red.

Answer 1

As the concentration of KCl increases , reaction moves in such a way so as to decrease the concentration of KCl. Reaction moves in backward direction and concentration of products will decrease.

According to Le Chatelier's principle if a system at equilibrium is subjected to a stress then the system behaves in such a way so as to reduce the stress. Effect of temperature : When temperature is increased then reaction shifts in that direction which absorbs heat and reduces temperature. In an exothermic reaction when temperature is increased then reaction shifts towards left direction and vice versa. In an endothermic reaction when temperature is increased then reaction shifts in right direction. Effect of pressure : When pressure increases volume decreases hence no. Of moles increases and reaction shifts in such a direction so as to reduce the number of moles i.e reaction shifts towards that side which have lesser no. of moles. Concentration : When concentration of product increases then reaction shifts towards product side and vice versa. When concentration of reactants increases then reaction shifts towards product side and vice versa. Catalyst : No effect on equilibrium.

Since the product contains a red colored complex ,as the concentration of products decrease the solution will become less red.

Answer -- turn the solution less red