Consider the following equations and select the false statement below: FeCl3(s)

Question

Consider the following equations and select the false statement below:

FeCl3(s) + 6H2O(l) ? Fe(H2O)63+(aq) + 3Cl?(aq)

Fe(H2O)63+(aq) + H2O(l) ? Fe(H2O)5(OH)2+(aq) + H3O+(aq)

A. if Fe(NO3)3(s) were used instead of FeCl3(s), different results would have been obtained

B. the hydrated iron(III) ion acts as an acid in the 2nd equation

C. the iron(III) ion withdraws electron density from the O?H bonds in the bonded water molecules, resulting in more polar O?H bonds

D. the iron(III) ion acts as a Lewis acid in the 1st equation

E. the iron(III) ion has a relatively high positive charge density

I know it's not D.

Explanation / Answer

Consider the following equations and select the false statement below:

FeCl3 (solid) + 6H2O (liquid) ---> [Fe(H2O)6]3+ (aqueous) + 3Cl- (aqueous)
[Fe(H2O)6]3+ (aqueous) + H2O (liquid) ---> [Fe(H2O)5(OH)]2+ (aqueous) + H3O+ (aq)

A. If Fe(NO3)3(solid) was used instead of FeCl3(solid), different results would have been obtained. FALSE statement as the results obtained will be the same, as shown below:

Fe(NO3)3 (solid) + 6H2O (liquid) ---> [Fe(H2O)6]3+ (aqueous) + 3NO3- (aqueous)
[Fe(H2O)6]3+ (aqueous) + H2O (liquid) ---> [Fe(H2O)5(OH)]2+ (aqueous) + H3O+ (aq)

B. The hydrated iron(III) ion acts as an acid in the 2nd equation. TRUE statement, as one water molecule of the hydrated iron ([Fe(H2O)6]3+) donates one proton (acidic property) to the water molecule.

C. The iron(III) ion withdraws electron density from the O-H bonds in the bonded water molecules, resulting in more polar O-H bonds. TRUE statement, as the O-H bonds are weakened by the iron (III) ion and hydrolysis occurs:
[Fe(H2O)6]3+ +   H2O ----> [Fe(H2O)5(OH)]2+ + H3O+
[Fe(H2O)5(OH)]2+(aq) + H2O(l)   ----> [Fe(H2O)4(OH)2]+(aq) + H3O+(aq)
[Fe(H2O)4(OH)2]+ (aq) + H2O(l) -----> [Fe(H2O)3(OH)3] (s) + H3O+ (aq)

D. The iron(III) ion acts as a Lewis acid in the 1st equation. TRUE statement, when FeCl3 dissolves in water the iron (III) is left Fe3+ , which accepts electrons from the water molecule.

E. The iron(III) ion has a relatively high positive charge density. TRUE statement, as is due to the high charge density on the iron that the O-H bonds are weakened and hydrolysis occurs.

ANSWER: THE FALSE STATEMENt IS OPTION A

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