Which formula-name combination is correct? Chlorite: ClO2 Dichlorine pentoxide: Cl2O7 Dichlorine heptoxide: Cl2O6 Chlorine monoxide: ClO Dichloride oxide: Cl2O
The Correct Answer and Explanation is:
The correct formula-name combination is:
Chlorine monoxide: ClO
Explanation
When naming chemical compounds, especially those involving nonmetals like chlorine and oxygen, the rules of nomenclature for molecular compounds apply. These rules use prefixes to indicate the number of atoms of each element in the compound. Let’s examine each combination to identify the correct one.
- Chlorite: ClO₂
Incorrect. “Chlorite” refers to a polyatomic ion with the formula ClO₂⁻, not a neutral compound. It carries a negative charge and is typically found in salts like sodium chlorite (NaClO₂). - Dichlorine pentoxide: Cl₂O₇
Incorrect. The name “dichlorine pentoxide” means 2 chlorine atoms and 5 oxygen atoms. However, Cl₂O₇ contains seven oxygen atoms. The correct name for Cl₂O₇ is dichlorine heptoxide. - Dichlorine heptoxide: Cl₂O₆
Incorrect. The formula Cl₂O₆ has 6 oxygen atoms. Therefore, the correct name should be dichlorine hexoxide. “Heptoxide” refers to seven oxygen atoms, which belongs to Cl₂O₇. - Chlorine monoxide: ClO
Correct. The prefix “mono-” indicates one oxygen atom, and since there is only one chlorine atom, no prefix is needed for chlorine. Hence, ClO is correctly named chlorine monoxide. - Dichloride oxide: Cl₂O
Incorrect. This is an outdated or ambiguous naming style. The modern IUPAC name uses prefixes for both elements. Cl₂O consists of two chlorine atoms and one oxygen atom, so the correct name is dichlorine monoxide.
Therefore, among the options given, “Chlorine monoxide: ClO” is the only correct formula-name match based on modern chemical nomenclature rules. Understanding and applying these rules ensures consistency and accuracy in chemical communication.
