If the standard cell potential for a given reaction is negative, will the reverse of the reaction given be spontaneous?

Yes.A negative standard cell potential (E°) indicates that the reaction, as written, is non-spontaneous under standard conditions. The reverse reaction, however, will have a standard cell potential of the same magnitude but opposite sign. Therefore, if the forward reaction has a negative E°, the reverse reaction will have a positive E°, and will be spontaneous under standard conditions.