Find the molarity of a sodium hydroxide solution obtained by dissolving 125.0 mg of sodium hydroxide in 50.ml volumetric flask.
The definition:
M = mols/L
You can get mols by mols NaOH = grams NaOH/molar mass NaOH
To find the molarity of a solution, you need to know the amount of solute (in moles) and the volume of the solution (in liters).
In this case, we have the amount of solute in milligrams (mg) and the volume of the solution in milliliters (ml). We first need to convert these values to moles and liters respectively.
1. Convert the amount of solute from milligrams to grams. There are 1000 milligrams in a gram, so the amount of sodium hydroxide in grams is:
125.0 mg ÷ 1000 = 0.125 g
2. Convert the volume of the solution from milliliters to liters. There are 1000 milliliters in a liter, so the volume of the solution in liters is:
50 ml ÷ 1000 = 0.05 L
Now that we have the amount of solute in moles (0.125 g) and the volume of the solution in liters (0.05 L), we can calculate the molarity using the following formula:
Molarity (mol/L) = Amount of solute (mol) ÷ Volume of solution (L)
3. Calculate the molarity:
Molarity = 0.125 g ÷ 0.05 L = 2.5 mol/L
Therefore, the molarity of the sodium hydroxide solution is 2.5 mol/L.