Question

Part i. you considered the equilibrium: fe3+(aq) + scn-(aq) fe(scn)2+(aq), and compared the color of the solutions in four test tubes. in the third test tube, you added 6 m naoh dropwise. how do you explain the formation of a precipitate and the shift in equilibrium in terms of lechatelier's principle?

Answer 1

The equilibrium will be shifted to lift with the formation of a brown gelatinous precipitate of Fe(OH)₃.

Step-by-step explanation:

• Le Chatelier's principle states that "when any system at equilibrium for is subjected to change in concentration, temperature, volume, or pressure, then the system readjusts itself to counteract the effect of the applied change and a new equilibrium is established that is different from the old equilibrium".

• The addition of NaOH will result in the formation of Fe(OH)₃ precipitate which has a brown gelatinous precipitate.

• The formation of this precipitate cause removal and decrease of Fe³⁺ ions.

• According to Le Chatelier's principle, the system will be shifted to lift to increase Fe³⁺ concentration and reduce the stress of Fe³⁺ removal and readjust the equilibrium again. So, the [Fe(SCN)²⁺] decreases.

• Increasing [Fe³⁺] will produce a yellow color solution that contains a brown gelatinous precipitate of Fe(OH)₃.