A student dissolves 4.00 g of NaOH in enough water to make 500.0 mL of solution. What is the molarity of the NaOH solution?

• A. 0.10 M
• B. 0.08 M
• C. 0.16 M
• D. 0.20 M

Answer: (C)

Verified step by step guidance

1. First, calculate the number of moles of NaOH dissolved. Use the formula: \(\text{moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}}\). The molar mass of NaOH is approximately 40.00 g/mol.
2. Next, convert the volume of the solution from milliliters to liters because molarity is expressed in moles per liter. Use the conversion: \$1\, \text{L} = 1000\, \text{mL}$.
3. Then, calculate the molarity (M) of the NaOH solution using the formula: \(M = \frac{\text{moles of solute}}{\text{liters of solution}}\).
4. Substitute the values you found for moles of NaOH and volume in liters into the molarity formula to find the concentration.
5. Finally, interpret the result to confirm which of the given options (0.10 M, 0.08 M, 0.16 M, 0.20 M) matches your calculated molarity.