What is the chemical name for Fe(NO2)2?
1) iron (II) nitrate 2) iron (II) nitrite 3) iron (III) nitrate 4) iron (III) nitride
The Correct Answer and Explanation is:
The correct answer is 2) iron (II) nitrite.
Explanation:
To determine the chemical name for Fe(NO₂)₂, we must first analyze its components:
- Identify the oxidation state of iron (Fe):
- In Fe(NO₂)₂, the nitrite ion (NO₂⁻) has a charge of -1. Since there are two nitrite ions, the total negative charge contributed by the nitrite ions is -2.
- To balance this, iron must have a charge of +2. Therefore, we designate iron as iron (II), indicating it has a +2 oxidation state.
- Understand the nitrite ion (NO₂⁻):
- The nitrite ion is composed of one nitrogen atom and two oxygen atoms. It is a polyatomic ion known for its -1 charge.
- Naming conventions:
- When naming a compound, the cation (positively charged ion) is named first, followed by the anion (negatively charged ion).
- Since we have iron (Fe) with a +2 oxidation state, it is named “iron (II).”
- The nitrite ion is simply referred to as “nitrite,” without any additional prefixes or suffixes.
Putting it all together, the name of Fe(NO₂)₂ is iron (II) nitrite.
Incorrect Options:
- Iron (II) nitrate: This would be represented as Fe(NO₃)₂, where the nitrate ion (NO₃⁻) has a -1 charge.
- Iron (III) nitrate: This would be Fe(NO₃)₃, indicating iron in a +3 oxidation state with three nitrate ions.
- Iron (III) nitride: This would imply the presence of the nitride ion (N³⁻), resulting in a completely different compound.
Thus, the only accurate name for Fe(NO₂)₂, considering its oxidation state and the type of ions present, is iron (II) nitrite.