Which of the following equations does not represent a redox reaction? Is my answer correct?

A. Yes, redox
Cu + 2AgNO₃ → 2Ag + Cu(NO₃)₂
Cu is oxidized as the oxidation number of Cu increases from 0 (in Cu) to +2 (in Cu(NO₃)₂).
AgNO₃ is reduced as the oxidation number of Ag decreases from +1 (in AgNO₃) to 0 (in Ag).

B. No, not redox
2CrO₄²⁻ + 2H⁺ → Cr₂O₇²⁻ + H₂O
The oxidation numbers keep unchanged. On the both sides, the oxidation numbers of Cr, O and H are both +6, -2 and +1 respectively.

C. Yes, redox
2SO₂ + O₂ → 2SO₃
SO₂ is reduced as the oxidation number of S increases from +4 (in SO₂) to +6 (in SO₃).
O₂ is oxidized as the oxidation number of O decreases from O (in O₂) to -2 (in SO₃).

D. Yes, redox
2H₂ + O₂ → 2H₂O
H₂ is oxidized as the oxidation number of H increases from 0 (in H₂) to +1 (in H₂O).
O₂ is reduced as the oxidation number of O decreases from 0 (in O₂) to -2 (in H₂O).

The answer: B. 2CrO₄²⁻ + 2H⁺ → Cr₂O₇²⁻ + H₂O

they are all redox.

Ok