What is the formula for copper (II) nitrite? CuN2O4 Cu(NO3)2 CuN2O6
The Correct Answer and Explanation is:
The correct formula for copper (II) nitrite is Cu(NO₂)₂.
To determine this formula, we need to consider the oxidation states of the elements involved. Copper (II) refers to copper with a +2 oxidation state, denoted as Cu²⁺. Nitrite is the polyatomic ion NO₂⁻, which carries a charge of -1. To form a neutral compound, the charges must balance. This means that one Cu²⁺ ion requires two NO₂⁻ ions to counterbalance its charge, resulting in Cu(NO₂)₂.
A common mistake is confusing nitrite (NO₂⁻) with nitrate (NO₃⁻). Copper (II) nitrate, which contains the NO₃⁻ ion, would have the formula Cu(NO₃)₂ instead. However, the question asks for the nitrite compound.
Chemical compounds follow strict rules of nomenclature and formula writing based on charge neutrality and empirical composition. For copper (II) nitrite, the subscript “2” in NO₂ indicates that two nitrite ions are required to balance the charge of one copper (II) ion.
Looking at the provided options:
- CuN₂O₄ does not correspond to any known copper nitrite formula.
- Cu(NO₃)₂ is copper (II) nitrate, which contains nitrate rather than nitrite.
- CuN₂O₆ does not follow conventional notation for copper nitrite.
Thus, Cu(NO₂)₂ is the correct answer. This compound consists of copper ions and nitrite ions, typically appearing as a crystalline solid with limited solubility in water. Its applications include specialized chemical processes and laboratory reactions. Understanding the difference between nitrite and nitrate is crucial in inorganic chemistry, as both ions exhibit distinct reactivity and bonding characteristics.
