Hot, concentrated aqueous sodium hydroxide and chlorine react as shown in the equation:
6NaOH + 3Cl2 → 5NaCl + NaClO3 + 3H2O
Which of the following statements is/are correct?
1 Chlorine has oxidation state + 5 in NaClO3.
2 This is an example of a disproportionation reaction.
3 Some of the oxygen in the hydroxide ions is oxidised.

Answer:

6) E

Statement 1 = Correct
In NaCIO3, each O has oxidation number -2. Since there are 3 Oxygen atoms, O has a total of -6.
Na = +1
Total oxidation number of NaCIO3 = 0
So, 01+ CI-6
CI
6-1+5
Statement 2 = Correct
A disproportionation reaction occurs when an element is both oxidised and reduced in the same reaction. In this reaction, Cl is oxidised and reduced at the same time.
In C12, oxidation state of CI = 0
In 5NaCl, oxidation state of CI = -1 (reduced)
In NaCIO3, oxidation state of CI = +5 (oxidised)
Statement 3 = Wrong
In hydroxide ions, oxidation state of oxygen = -2 So, it is not oxidised