Question 4 Consider the structure of Famotidine (Pepcid) below, where a region of interest has been boxed. a) Circle the guanidine functional group in famotidine. b) Do you expect this substituted guanidine to have a higher or lower pKa than an unsubstituted guanidine? (circle one) Why? c) Draw out all bonds between the atoms in the boxed region of famotidine d) Will famotidine have a formal charge at physiological pH (7.4)? Why or why not