Iron exhibits +2 and +3 oxidation states. Which of the following statements about iron is incorrect?

(A) Ferrous oxide is more basic in nature than the ferric oxide.

(B) Ferrous compounds are relatively more ionic than the corresponding ferric compounds.

(C) Ferrous compounds are less volatile than the corresponding ferric compounds.

(D) Ferrous compounds are more easily hydrolyzed than the corresponding ferric compounds.

Choose the correct answer from the options given below:

(D) Only

The correct answer is option 4. (D) Only.

Let us look at each of the given statements:

(A) Ferrous oxide is more basic in nature than the ferric oxide: Ferrous oxide \((FeO)\) with a \(+2\) oxidation state for iron is more basic than ferric oxide \((Fe_2O_3)\) with a +3 oxidation state. So, statement (A) is correct.

(B) Ferrous compounds are relatively more ionic than the corresponding ferric compounds: Lower oxidation states generally lead to more ionic compounds due to a larger positive charge on the metal cation. Thus, ferrous compounds tend to be more ionic than ferric compounds. So, statement (B) is also correct.

(C) Ferrous compounds are less volatile than the corresponding ferric compounds: Volatility often increases with decreasing ionic character and molecular weight. While \(FeO\) might be slightly more ionic, the significant difference in molecular weight \((FeO: 72\, \ vs.\, \ Fe_2O_3: 159.69) makes ferric oxide likely more volatile. However, the statement doesn't claim absolute volatility but "less volatile," so the answer cannot be definitively determined based on this point alone.

(D) Ferrous compounds are more easily hydrolyzed than the corresponding ferric compounds: Higher oxidation states often lead to increased attraction with water molecules due to a higher positive charge on the metal cation. This can make hydrolysis (reaction with water) more likely. So, statement (D) is the most likely to be incorrect.

Therefore, only statement (D) about ferrous compounds being less easily hydrolyzed than ferric compounds is likely incorrect.