What is the molarity of NaOH in the solution prepared by dissolving its 4 g in 250 ml of solution? (The atomic mass of sodium is 23)

Molarity (M) is defined as the number of moles of solute dissolved in one litre of solution. The calculation for this problem is as follows:

• Step 1: Calculate the molar mass of NaOH. The atomic masses are Na = 23, O = 16, and H = 1. Therefore, Molar Mass = 23 + 16 + 1 = 40 g/mol.
• Step 2: Calculate the number of moles of NaOH. Moles = Given Mass / Molar Mass = 4 g / 40 g/mol = 0.1 mol.
• Step 3: Convert the volume of the solution to litres. Volume = 250 ml = 250/1000 L = 0.25 L.
• Step 4: Calculate Molarity. Molarity = Moles / Volume (L) = 0.1 mol / 0.25 L = 0.4 M.

The result is 0.4 M. In the provided options, '0-4 M' is a typographical representation of 0.4 M.