An unknown weak base with a concentration of 0.0910 M has a pH of 11.90. What is the Kb of this base?

An aqueous solution of potassium hydroxide is standardized by titration with a 0.194 m solution of hydrobromic acid. if 25.2 ml of base are required to neutralize 24.2 ml of the acid, what is the molarity of the potassium hydroxide solution? m potassium hydroxide

Asolution contains 225 g of sodium chloride, nacl, dissolved in enough water to make a 0.25 l of solution. what is the molarity of the solution?

How is it possible for someone to put an ear to a wall and hear someone in the next room?     a.sound waves can travel though solids.    b.the waves travel from room to room via air.    c.there must be some air in the wall so the sound can travel through it.    d.sound waves change to electromagnetic waves and then back again.