Which of the following reactions are disproportionation reactions? (i) 2Cu Cu Cu → (ii) 3MnO 4H 2MnO MnO 2H O → (iii) 2KMnO K MnO MnO O → (iv) 2MnO 3Mn 2H O 5MnO 4H → Select the correct option from the following. (NEET 2019)

Disproportionation reactions are those in which the same element/compound gets oxidised and reduced simultaneously. 2 0 2Cu Cu Cu → 6 7 4 2 4 4 2 2 3Mn O 4H 2Mn O MnO 2H O → 47. The oxidation state of Cr in CrO₅ is (NEET 2019) (a) – 6 (b) + 12 (c) + 6 (d) + 4 CrO₅ has butterfly structure having two peroxo bonds. Peroxo oxygen has –1 oxidation state. Let oxidation state of Cr be ‘x’ 5 CrO : x 4 1 1 2 0 x 6 >> 48. What is the oxidation number of Cr in Na₂Cr₂O₇ ? (JIPMER 2019) (a) 2 (b) 6 (c) 10 (d) 16 Let the oxidation number of Cr in Na₂Cr₂O