1. Fluorine reacts with hot concentrated NaOH solution to form oxygen.
The reaction is as follows:
10F2+20NaOH→20NaF+10O2+H2O
2. Fluorine reacts with water to form oxygen.
2F2+2H2O→O2+4F−+4H+.
3. Chlorine reacts with cold dilute NaOH solution to form sodium chloride, sodium hypochloride and water. Oxygen is not formed in the reaction.
Cl2+NaOH→NaCl+NaOCl+H2O
4. CaOCl2 reacts with small amount of dilute H2SO4 to produce oxygen.
2CaOCl2+H2SO4→CaCl2+CaSO4+2HClO
HClO→HCl+O
Hence, the only reaction among the four which produce no oxygen is between Cl2 and NaOH (cold, dilute).
Hence, the correct option is C.