The Elementary Reaction HBr(g) + Br(g) $\rightarrow$ H(g) + Br₂(g) Is Endothermic

The elementary reaction HBr(g) + Br(g) $\rightarrow$ H(g) + Br₂(g) is endothermic.
A) Would you expect the rate constant for the back reaction to be smaller or larger than that for the forward reaction? Explain, briefly.
B) Draw a fully-labeled reaction energy diagram for this reaction, showing the locations of the reactants, products and transition state.