This answer is not correct. You have multiplied by the 2 moles/liter term and divided by the 0.4 moles/liter term. This problem is based on the algebraic relationship... volume₁ x concentration₁ = volume₂ x concentration₂. Remember that when you solve this equation for one of the terms, you must do the same operation on both sides of the equal sign. In this case, we need to divide both terms by the 2 M NaCl concentration term so that the units of concentration (molarity) cancel. You did correctly convert the units of liters to milliliters which is also necessary in order to solve this problem since the units on both sides of the equal sign must be the same.