What is the oxidation number of chlorine in sodium chlorite, NaClO2

What is the oxidation number of chlorine in sodium chlorite, NaClO2? a) -1 b) +1 c) +3 d) +5 e) +7

The Correct Answer and Explanation is:

The correct answer is c) +3.

Explanation:

To determine the oxidation number of chlorine in sodium chlorite (NaClO₂), we can follow these steps:

1. Assign oxidation numbers to other elements:
   • Sodium (Na) is in Group 1 of the periodic table and typically has an oxidation number of +1 in its compounds.
   • Oxygen (O), in most of its compounds, has an oxidation number of -2.
2. Set up the equation:
   The compound is neutral overall, so the sum of the oxidation numbers must equal zero. In sodium chlorite (NaClO₂), we have one sodium ion (Na⁺), one chlorine atom (Cl), and two oxygen atoms (O₂).
3. Write the equation for the sum of oxidation numbers:
   • Sodium contributes +1.
   • Chlorine contributes an unknown oxidation number, let’s call it x.
   • Each oxygen contributes -2, so for two oxygens, that’s -4.
   Now, set up the equation: (+1)+x+2(−2)=0(+1) + x + 2(-2) = 0(+1)+x+2(−2)=0 Simplify the equation: +1+x−4=0+1 + x – 4 = 0+1+x−4=0 x−3=0x – 3 = 0x−3=0 x=+3x = +3x=+3

Thus, the oxidation number of chlorine in NaClO₂ is +3.

Conclusion:

In sodium chlorite (NaClO₂), the chlorine atom has an oxidation number of +3, which is consistent with the choice c) +3.