What is the change in oxidation number of carbon in the following reaction?
CH₄(g) + 4Cl₂(g) $$ \to $$ CCl₄(l) + 4HCl(g)

Which of the following reactions are disproportionation reaction?

(a) 2Cu⁺ $$ \to $$ Cu²⁺ + Cu⁰
(b) 3MnO₄²⁺ + 4H⁺ $$ \to $$ 2MnO₄^- + MnO₂ + 2H₂O
(c) 2KMnO₄ $$\buildrel \Delta \over \longrightarrow $$ K₂MnO₄ + MnO₂ + O₂
(d) 2MnO₄^- + 3Mn²⁺ + 2H₂O $$ \to $$ 5MnO₂ + 4$${H^ \oplus }$$

Select the correct option from the following :

For the redox reaction,
MnO₄^– + C₂O₄ ^2– + H⁺ $$ \to $$ Mn²⁺ + CO₂ + H₂O
The correct coefficients of the reactants for the balanced equation are