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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? a. The addition of NaOH produced the precipitate, Fe(OH)3, which removed Fe3+ from the system. To reduce the stress of the removal of Fe3+ and to re-establish equilibrium, the system shifted to the left increasing [Fe3+] and decreasing the [Fe(SCN)2+]. Increasing the [Fe3+] produced a yellow colored solution. b. The addition of NaOH produced the precipitate, NaSCN, which removed SCN- from the system. To reduce the stress of the removal of SCN- and to re-establish equilibrium, the system shifted to the left increasing [SCN-] and decreasing the [Fe(SCN)2+]. Increasing the [SCN-] produced a yellow colored solution. c. The addition of NaOH produced the precipitate, Fe(SCN)(OH)2, which removed Fe(SCN)2+ from the system. The removal of Fe(SCN)2+ from the system caused the deep red color to disappear leaving only the yellow color.

Respuesta :

superman1987

Answer:

a. The addition of NaOH produced the precipitate, Fe(OH)₃, which removed Fe³⁺ from the system. To reduce the stress of the removal of Fe³⁺ and to re-establish equilibrium, the system shifted to the left increasing [Fe³⁺] and decreasing the [Fe(SCN)²⁺]. Increasing the [Fe³⁺] produced a yellow colored solution.

Explanation:

  • The addition of NaOH to the test tube contents will result a precipitate of Fe(OH)₃ which has a reddish brown ppt.
  • So, this cause removal of Fe³⁺ which disturb the equilibrium.
  • According to Le Chatelier's Principle: if the equilibrium of a reaction is disturbed by an external stress, the system will be shifted to the other directio to attain the equilibrium again.
  • Thus, to reduce the stress of the removal of Fe³⁺ and to re-establish equilibrium, the system shifted to the left increasing [Fe³⁺] and decreasing the [Fe(SCN)²⁺].
  • Increasing the [Fe³⁺] produced a yellow colored solution.

So, the right choice is:

a. The addition of NaOH produced the precipitate, Fe(OH)₃, which removed Fe³⁺ from the system. To reduce the stress of the removal of Fe³⁺ and to re-establish equilibrium, the system shifted to the left increasing [Fe³⁺] and decreasing the [Fe(SCN)²⁺]. Increasing the [Fe³⁺] produced a yellow colored solution.

mickymike92

According to equilibrium principle,

  • the addition of NaOH produced the precipitate, Fe(OH)3, which removed Fe3+ from the system.
  • To reduce the stress of the removal of Fe3+ and to re-establish equilibrium, the system shifted to the left increasing the concentration of Fe3+ and decreasing the concentration of iron (ii) thiocyanate.
  • Increasing the concentration of Fe3+ produced a yellow colored solution; option A

How does addition of 6M NaOH affect the equilibrium of the system?

When 6M NaOH is added surprise to the equilibrium of the system, a precipitate is formed and a yellow-coloured solution is observed.

The explanation for this observation is as follows:

Addition of 6M NaOH results in the formation of iron(iii) oxide which is insoluble and precipitates.

Due to the the removal of Fe3+ in the form of insoluble precipitate, its concentration decrease.

In order to restore equilibrium, more Fe3+ is produced reducing the concentration of the iron (ii) thiocyanate and the solution turns yellow.

Therefore, based on equilibrium principle, the correct explanation is option A:

  • the addition of NaOH produced the precipitate, Fe(OH)3, which removed Fe3+ from the system.
  • To reduce the stress of the removal of Fe3+ and to re-establish equilibrium, the system shifted to the left increasing concentration of Fe3+ and decreasing the concentration of iron (ii) thiocyanate.
  • Increasing the concentration of Fe3+ produced a yellow colored solution.

Learn more about equilibrium at: https://brainly.com/question/24735820

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