Which of the following statements is false regarding the collecting duct? (1) Collecting duct is a straight duct (2) It extends from the cortex to medulla (3) Large amount of water could be reabsorbed from it to produce concentrated urine (4) Small amount of urea diffuses out from it into the medulla to keep up the osmolarity (5) It plays a role to maintain pH and ionic balance of blood by the selective secretion of H+ and K+ ions