What is the correct systematic name of the compound NH4ClO3?

Introduction / Context:
Polyatomic ions allow elements like chlorine to form several oxy anions with different oxidation states. Correctly naming compounds that contain these ions is a standard skill in inorganic chemistry. This question focuses on NH4ClO3 and checks whether you can identify the ammonium cation and the correct chlorine oxy anion present in the formula, and then give the proper systematic name.

Given Data / Assumptions:

• The formula is NH4ClO3.
• The cation is NH4 plus, the ammonium ion.
• The anion contains chlorine and oxygen with formula ClO3 minus.
• Options include several similar sounding names such as chloride, chlorate, and chlorine.

Concept / Approach:
In ionic nomenclature, NH4 plus is the ammonium ion. The chlorine oxy anion family includes ClO minus (hypochlorite), ClO2 minus (chlorite), ClO3 minus (chlorate), and ClO4 minus (perchlorate). In NH4ClO3, the anion part ClO3 minus is chlorate. We place the cation name first and the anion name second, giving ammonium chlorate. Chloride would correspond to Cl minus, not ClO3 minus, and names like chlorane or chlorine are not correct oxy anion names.

Step-by-Step Solution:
Step 1: Identify NH4 plus as the ammonium ion, a common polyatomic cation. Step 2: Identify ClO3 minus as a chlorine oxy anion with three oxygen atoms. Step 3: Recall the naming pattern: ClO minus is hypochlorite, ClO2 minus is chlorite, ClO3 minus is chlorate, and ClO4 minus is perchlorate. Step 4: Therefore, ClO3 minus corresponds to chlorate. Step 5: Combine names, putting the cation first and anion second, which gives ammonium chlorate. Step 6: Check that none of the other names match the formula NH4ClO3; they either refer to different anions or are not standard names.

Verification / Alternative check:
Consulting tables of common ions in textbooks confirms that ClO3 minus is chlorate and NH4 plus is ammonium. Chemical listings and safety data sheets for NH4ClO3 label it as ammonium chlorate. The stoichiometry is one ammonium ion and one chlorate ion per formula unit, which matches the naming method of cation plus anion names with no prefixes for this type of ionic compound.

Why Other Options Are Wrong:
Ammonium chloride: This name would correspond to NH4Cl, where the anion is chloride (Cl minus), not ClO3 minus.
Ammonium chlorane: This is not a recognised standard name in common inorganic nomenclature and does not match any usual oxy anion pattern.
Ammonium chlorine: This suggests elemental chlorine or an undefined ionic form; it is not a proper IUPAC style name for an oxyanion salt.

Ammonium hypochlorite: This would correspond to NH4ClO, where the anion is ClO minus (hypochlorite), not ClO3 minus.

Common Pitfalls:
Students often mix up the series of chlorine oxy anions because their names sound similar. A useful memory aid is to remember that more oxygen means a higher oxidation state and a different suffix or prefix: hypochlorite has the fewest oxygen atoms, chlorite and chlorate are intermediate, and perchlorate has the most. Another pitfall is to ignore the ammonium cation and focus only on the chlorine part. Always break the formula into cation and anion to name such compounds correctly.

Final Answer:
The systematic name of NH4ClO3 is ammonium chlorate.