What is the molarity of a solution that has 23.0 g of NaOH dissolved in 0.500 L of solution?

Answer: 1.15M

Explanation:

Given that,

Amount of moles of NaOH (n) = ?

Mass of NaOH in grams = 23.0g

For molar mass of NaOH, use the atomic masses: Na = 23g; O = 16g; H = 1g

NaOH = (23g + 16g + 1g)

= 40g/mol

Since, n = mass in grams / molar mass

n = 23.0g / 40.0g/mol

n = 0.575 mole

Volume of NaOH solution (v) = 0.5 L

Concentration of NaOH solution (c) = ?

Since concentration (c) is obtained by dividing the amount of solute dissolved by the volume of solvent, hence

c = n / v

c = 0.575 mole / 0.5L

c = 1.15 M (M stands for molarity and gives the concentration in moles per litres)

Thus, the molarity of the solution is 1.15M