Which of the following solutions will have the greatest molarity?

• A. 1 mole of NaCl dissolved in 1 liter of water
• B. 2 moles of NaCl dissolved in 2 liters of water
• C. 2 moles of NaCl dissolved in 1 liter of water
• D. 1 mole of NaCl dissolved in 2 liters of water

Answer: (C)

Verified step by step guidance

1. Recall that molarity (M) is defined as the number of moles of solute divided by the volume of the solution in liters. The formula is: \(M = \frac{\text{moles of solute}}{\text{volume of solution in liters}}\).
2. Calculate the molarity for each solution by dividing the given moles of NaCl by the given volume of water (in liters). For example, for 1 mole in 1 liter, molarity is \(\frac{1}{1}\).
3. Compare the molarities calculated for each solution to determine which one has the greatest value.
4. Remember that increasing the number of moles or decreasing the volume will increase the molarity, so pay attention to both factors in each case.
5. Identify the solution with the highest molarity based on your calculations and comparisons.