Effect of Concentration Change

• What color is observed after FeSCN2+ was added?

  Red
• What was the shift in equilibrium after FeSCN2+ was added?

  No change
• What was the explanation after FeSCN2+ was added?

  Addition of Fe(NO3)3 increases the concentration

  causing equilibrium to shift in forward direction.
• What color is observed after Fe(NO3)3 is added?

  Dark Red
• What was the shift in equilibrium after Fe(NO3)3 is added?

  Forward reaction or to the right
• What was the explanation after Fe(NO3)3 is added?

  Intensity of the color depends on the concentration

  of the reactants causing equilibrium to shift in forward direction. The Fe+ ions from iron (iii) nitrate

  react with SCN- from Potassium thiocyanate producing deep red color
• What was the observed color when KSCN was added?

  Pale Red
• What was the shift in equilibrium when KSCN was added?

  Forward reaction or to the right
• What was the explanation when KSCN was added?

  Addition of KSCN increases the concentration

  of the solution causing equilibrium to shift in forward

  direction.
• What was the color observed when AgNO3 was added?

  Colorless
• What was the shift in equilibrium when AgNO3 was added?

  Backward reaction or to the left
• What was the explanation when AgNO3 was added?Addition of AgNO3 to the solution Ag+ions are introduced and reacts with SCN-, reducing SCN- as

  AgSCN is removed, the concentration is reduced and the reaction shifts to the left producing colorless

  complex.
• What was the color observed when NH3 was added?

  No change from standard
• What was the shift in equilibrium when NH3 was added?

  Backward reaction or to the left
• What was the explanation when NH3 was added?

  Addition of NH3 binds to the free Fe+3 ions so the reaction tries to restore the last Fe+3 ions by shifting the equilibrium to the left based on Le Chatelier’s principle, if the change is imposed on a system at

  equilibrium, the system will react to counteract the

  change.