answer is 10^-1 . option number d.
when sodium hydride (nah) is dissolved in water, the following reaction occurs:
hence option (3) is the correct answer.
hydride ions are stronger base means will react with water to form hydroxide ion and water.
since, hydride ion is a "stronger base", it will take from water to forms whereas will remains in the solution. is called as "bronsted-lowry acid-base" theory.
theory states that an acid can give ions whereas a base can accept ions.