Which equation(s) do you need to reverse in order to calculate the overall equation for the formation of HCN and H2 from NH3 and CH4? Check all that apply.

Reverse A so that NH3 is a reactant: 2NH3 → N2 + 3H2. Reverse B so that CH4 is a reactant: CH4 → C + 2H2; use it twice to match the other equations. Keep C as written, since it produces HCN. Adding the equations and canceling N2, C, and excess H2 gives 2NH3 + 2CH4 → 2HCN + 6H2, which simplifies to NH3 + CH4 → HCN + 3H2.

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