Here's how to calculate the concentration in mv% (mass/volume percent) of the NaCl solution:

1. Convert Liters to Milliliters:

* 2.5 L * 1000 mL/L = 2500 mL

2. Calculate the Mass/Volume Percent:

* Formula: mv% = (mass of solute / volume of solution) * 100%

* Plug in values: mv% = (50 g NaCl / 2500 mL solution) * 100%

* Calculate: mv% = 2%

Therefore, the concentration of the NaCl solution is 2% mv.