Calculate the molarity of NaOH in the solution prepared by dissolving its 4g in water to make a solution of 250ml.

To calculate the molarity (M) of a solution, you can use the formula:

Molarity (M) = (moles of solute) / (volume of solution in liters)

Given that you have dissolved 4 grams of NaOH in 250 ml of water, we need to follow these steps:

Step 1: Calculate the moles of NaOH.
You can use the molar mass of NaOH to calculate the moles:

Molar mass of NaOH = 22.99 g/mol (Na) + 15.999 g/mol (O) + 1.007 g/mol (H) = 39.997 g/mol

Moles of NaOH = (mass) / (molar mass) = 4 g / 39.997 g/mol ≈ 0.100 mol

Step 2: Convert the volume to liters.
The volume given is in milliliters (ml), so we need to convert it to liters:

Volume = 250 ml / 1000 = 0.250 L

Step 3: Calculate molarity.
Now we can plug the values into the molarity formula:

Molarity (M) = (moles of solute) / (volume of solution in liters)
Molarity (M) = 0.100 mol / 0.250 L = 0.4 M

The molarity of the NaOH solution prepared by dissolving 4 grams of NaOH in 250 ml of water is approximately 0.4 M.