Which formula/name pair is incorrect? A) Mn(NO2)2 manganese(II) nitrite B) Mn(NO3)2 manganese(II) nitrate C) Mg(NO3)2 magnesium nitrate D) Mg(MnO4)2 magnesium permanganate E) Mg3N2 magnesium nitrite
The Correct Answer and Explanation is :
The incorrect formula/name pair is E) Mg₃N₂ magnesium nitrite.
Explanation:
To understand why this pair is incorrect, we need to break down each compound and its corresponding name.
- A) Mn(NO₂)₂ manganese(II) nitrite:
- The compound is manganese(II) nitrite.
- Mn (Manganese) has a 2+ charge in this case, and the nitrite ion is NO₂⁻.
- Since there are two NO₂⁻ ions to balance the charge of Mn²⁺, the formula is Mn(NO₂)₂. This is correct.
- B) Mn(NO₃)₂ manganese(II) nitrate:
- The compound is manganese(II) nitrate.
- Mn²⁺ is correctly paired with two nitrate ions (NO₃⁻), so the formula Mn(NO₃)₂ is correct.
- C) Mg(NO₃)₂ magnesium nitrate:
- The compound is magnesium nitrate.
- Mg²⁺ is correctly paired with two nitrate ions (NO₃⁻), so the formula Mg(NO₃)₂ is correct.
- D) Mg(MnO₄)₂ magnesium permanganate:
- The compound is magnesium permanganate.
- Mg²⁺ is paired with two permanganate ions (MnO₄⁻), and the formula Mg(MnO₄)₂ is correct.
- E) Mg₃N₂ magnesium nitrite:
- The compound is incorrectly named.
- The formula Mg₃N₂ corresponds to magnesium nitride, not magnesium nitrite.
- Magnesium nitride consists of magnesium (Mg²⁺) and nitride (N³⁻) ions, and in this case, three Mg²⁺ ions balance two N³⁻ ions, forming Mg₃N₂.
- Nitrite (NO₂⁻) would require a different composition (Mg(NO₂)₂), not Mg₃N₂.
Therefore, the correct name for Mg₃N₂ is magnesium nitride, not magnesium nitrite, making E the incorrect pair.