The correct option is A Cr2O2−7+2⊝OH→CrO2−4+H2O
PCl5→PCl3+Cl2
+5 +3 redox reaction
2Ca(OH)2+2Cl2→Ca(ClO)2+CaCl2+2H2O
0 +1 -1 redox reaction
SO2−5+2I⊝+2H⨁→I2+SO2−4
-1 0 redox reaction
Cr2O2−7+2⊝OH→CrO2−4+H2O
+6 +6
Since, there is no change in oxidation state in this reaction, it is not a redox reaction.