The Effect Of Concentration Changes On Equilibria
Reversible Reaction: Fe3+(aq) + SCN-(aq) ↔ Fe(SCN)2+(aq)
* NaOH -> the equilibrium position will shift to the left because Fe(OH)3 will be produced, making the concentration of Fe3+ lower.
* AgNO3 -> the equilibrium position will shift to the left because NO3 will react with Fe producing FeNO3 and making the concentration of Fe3+ lower.
* KSCN -> the equilibrium position will shift to the right because K will dissociate from the SCN making the concentration of SCN- increase.
* NH4Cl-> the equilibrium position will shift to the left because NH4 will react with SCN- decreasing the quantity of SCN_
* NaCl-> the equilibrium position will shift to the left because Cl will react with Fe3+ producing FeCl and decreasing the amount of Fe3+ .
Substance | Colour Change | Eq. Position Indication |
NaOH | Turns clearer into a more orange tone with less transparency but not to much turbidity. | Left. |
AgNO3 | The colour of the solution turns lighter, into a yellow tone which seems dense with solid particles. | Left. |
KSCN | The colour of the solution turns darker, into a vivid red colour with less transparency than the control test tube. | Right. |
NH4Cl | The solution turns lighter, into a yellow dense orange with almost null transparency. | Left. |
NaCl | The solution turns a lot lighter and colourless with abundance of some solid particles in the bottom. | Left. |
F: Control Solution
The result of NaOH indicates that the equilibrium position shifted to the left.In molecular terms this is explained by the following facts:
The iron (III) ions (Fe3+) reacted with sodium hydroxide ions (Na+OH-),...