Determine which reaction has the highest activation energy. A. Melting ice B. Reacting metal and acid C. Burning charcoal D. Combusting gasoline

C. Burning charcoal

Explanation:

Charcoal is a solid fuel. We normally expect a solid fuel to possess a very high activation energy. Activation energy refers to the energy barrier that must be crossed by reactants in order to be converted into products. A high activation energy implies that the reaction may not be spontaneous at ordinary temperatures and a large external energy must be supplied before the reaction proceeds.

Charcoal is not as spontaneously flammable as gasoline. This implies that a greater energy is required to initiate the combustion of charcoal compared to gasoline. This further buttresses the fact that the activation energy for the combustion of gasoline is less than that for the combustion of charcoal.

The reaction of metals with acid is quite spontaneous at ordinary temperatures for highly reactive metals hence it does not have a high activation energy. The melting of ice is not a chemical reaction hence we can't talk about its activation energy.

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)