Oxidation Reduction

[Whiteshoes]

My reasoning: In the reactant side Iodide is -1 and product side since it is by itself it is 0. so it lost an electron = oxidized right?

31 BC

• Equilibrium (Gen Chem)

Some compounds are only slightly soluble in water. When silver iodide is placed in water, an equilibrium is quickly established between free ions and the solid precipitate of those ions as described by the following reaction:

AgI(s)

Ag+ (aq) + I– (aq)
Reaction 1​

which expresses that the ions Ag+ and I– are in dynamic equilibrium with AgI(s). The equilibrium constant, defined as the product of the concentration of silver ions and the concentration of iodide ions, is called the solubility product and denoted Ksp:

Ksp = [Ag+][I–]​

Figure 1 shows a plot of the solubility of silver iodide in an aqueous solution containing varying concentrations of sodium iodide.

Figure 1

Solubility of silver iodide in sodium iodide​

Which one of the following is true of Reaction 1?

A.
Ag is oxidized as it dissolves.

B.
I is oxidized as it dissolves.

C.
The oxidation state of Ag does not change.

Correct Answer

D.
The oxidation state of Ag decreases with precipitation.

Explanation: ​

C. Reaction 1 is not a redox reaction. The oxidation states of Ag and I in AgI(s) are +1 and –1, respectively, and neither changes during dissolving.

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[milski]

The product is an ion, I-, it still has the electron. Same for Ag, but the other way, it's Ag+.

 

[IncognitoGuy]

My reasoning: In the reactant side Iodide is -1 and product side since it is by itself it is 0. so it lost an electron = oxidized right?

31 BC

• Equilibrium (Gen Chem)

Some compounds are only slightly soluble in water. When silver iodide is placed in water, an equilibrium is quickly established between free ions and the solid precipitate of those ions as described by the following reaction:

AgI(s)

Ag+ (aq) + I– (aq)
Reaction 1​

which expresses that the ions Ag+ and I– are in dynamic equilibrium with AgI(s). The equilibrium constant, defined as the product of the concentration of silver ions and the concentration of iodide ions, is called the solubility product and denoted Ksp:

Ksp = [Ag+][I–]​

Figure 1 shows a plot of the solubility of silver iodide in an aqueous solution containing varying concentrations of sodium iodide.

Figure 1

Solubility of silver iodide in sodium iodide​

Which one of the following is true of Reaction 1?

A.
Ag is oxidized as it dissolves.

B.
I is oxidized as it dissolves.

C.
The oxidation state of Ag does not change.

Correct Answer

D.
The oxidation state of Ag decreases with precipitation.

Explanation: ​

C. Reaction 1 is not a redox reaction. The oxidation states of Ag and I in AgI(s) are +1 and –1, respectively, and neither changes during dissolving.

If it is on its own, its oxidation state is typically the charge. Thus, it would be +1 on both the left and right, thus ruling out A and D. B is also wrong for obvious reasons, leaving you with C.

So, Ag would be +1 for the reactant because I is -1, and the overall Ox. # must equal the charge of a compound, which in this case is 0. Then, on the right, the ions are on their own and charges typically correspond to oxidation #, still leading you to find that Ag is +1 and I is -1.

 

[MedPR]

I2 would have an oxidation state of 0. I- has an oxidation state of -1.