Normal saline solution is

Why the vapour pressure of saline solutions is lower than that of pure water ?

$ The patients of cholera, vomitting and dysentary are given intravenous drip of saline solution. ! The saline solution kills the disease causing micro-organisms, after vomitting and dysentary.

Assertion: The patients of cholera, vomiting and dysentery are given intravenous drip of saline solution. Reason: The saline solution kills the disease causing micro-organisms, after vomiting and dysentery.