An exothermic reaction X $$ \to $$ Y has an activation energy 30 kJ mol^$$-$$1. If energy change $$\Delta$$E during the reaction is $$-$$20 kJ, then the activation energy for the reverse reaction in kJ is ___________. (Integer answer)

Dichromate ion is treated with base, the oxidation number of Cr in the product formed is ___________.

Number of bridging CO ligands in [Mn₂(CO)₁₀] is __________.

Consider the following reaction

$$MnO_4^ - + 8{H^ + } + 5{e^ - } \to M{n^{ + 2}} + 4{H_2}O,{E^o} = 1.51V$$.

The quantity of electricity required in Faraday to reduce five moles of $$MnO_4^ - $$ is ___________. (Integer answer)