Ascorbic C3H7O4COOH,also known as VitaminC, is an essential Vitamin for all mammals. Among mammals, only humans, monkeys and guinea pigs cannot synthesis it in their bodies LA for ascorbic acid is 7.9*10^-5. Calculate [H3O+] and pH in a 0.110M solution of the acid.

Answer 1

Did you mean synthesize? Did you mean Ka = 7.9E-5?
Call ascorbic acid Has, then
...............Has ==> H^+ + as^-
I.............0.110........0..........0
C............-x..............x..........x
E.........0.110-x........x...........x

Write the Ka expression for ascorbic acid, substitute the E line above and solve for H^+ = (H3O^+). Convert that to pH by pH = -log(H^+).
Post your work if you get stuck.