What is the molarity of a 250.0 milliliter aqueous solution of sodium hydroxide that contains 15.5 grams of solute

There are a number of ways to express concentration of a solution. This includes molarity. Molarity is expressed as the number of moles of solute per volume of the solution. The concentration of the solution is calculated as follows:

Molarity = 15.5 g NaOH (1 mol NaOH / 40 g NaOH) /.250 L solution

Molarity = 1.55 M