Question

A student doing the experiment in this module extendedthe study of the [CoCl₄]^2- ion /[Co(H₂0)₆]²⁺ ionequilibrium. Whatis the net ionic equation for this reaction?

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Net ionic reaction	a. [Co(H2O)6]2+ + 4Cl- <--> [CoCl4]2- + 6 H2O
	b. [CoCl4]2- <--> [Co(H2O)6]2+
	c. [CoCl4]2- + 4Cl- <--> [Co(H2O)6]2+ 6 H2O
	d. [CoCl4]2- + 6 H2O <--> [Co(H2O)6]2+ + 4Cl-
	e. No right answer
	f. CoCl2 + 2HCl <--> [CoCl4]2- + 2H+

Matchingpairs

Net ionic reaction

- Select choice -abcdef

A student doing the experiment in this module extended the study ofthe [CoCl₄]^2- ion /[Co(H₂0)₆]²⁺ ionequilibrium. Inone test tube, the student added silver nitrate (AgNO₃)to a blue equilibrium mixture prepared from CoCl₂. The reaction mixturebecame pink andcloudy, and a white precipitate settled out leaving a clear, pinksolution. The student identified the precipitate as silverchloride, AgCl.

(i) Whichstatement explains best how these observations are consistent withLe Chatelier's principle,

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How are these observations consistent with LeChatelier'sPrinciple?	a. The pink color is the result of more [Co(H20)6] 2+ becausethe silver reacts with chloride and shifting the reaction to theright.
	b. The CoCl2 releases its chloride to AgNO3 forming [CoCl4]2-(pink) and AgCl (white precipitate).
	c. The reaction shifts to the left as the silver reacts withthe excess chloride resulting in more [CoCl4] 2- formation.
	d. AgNO3 combines with [Co(H2O)6]2+ resulting in the reactionto shift to the right. This causes [CoCl4]2- to precipitate out ofsolution.
	e. The pink color is the result of [CoCl4]2-, because AgNO3removes the Cl from [CoCl4]2- resulting in the reaction shitting tothe left.

Matching pairs

How are these observations consistent withLeChatelier's Principle?

- Select choice -abcde

Answer 1

In the study of[CoCl₄]^2- ion /[Co(H₂0)₆]²⁺ ionequilibrium, the two ionsgiven interconvert to each other.Hence the net ionic equation, which shows the reaction between thetwo ions is correct.d is the right answer as it shows the correct reaction in thecorrect direction from CoCl4 to Co(H2O) 6[CoCl4]2-+6 H2O <--> [Co(H2O)6]2+ + 4Cl-When silver nitrate is added to the mixture and silverchloride is precipitated, it shows that chloride ion is removedfrom the equilibrium mixture. Thismeans that the concentration ofCoCl4 in the mixture decreases. So according to Le-Chatlier'sprinciple, the equilibrium shifts towards the left.Thatmeans some amount of Co(H2O)6 dissociates to give Co Cl4.Hence answer is c