The strength of Nitro concentrate for solution for infusion is 5 mg/ml. One 2 ml ampoule of concentrate for solution for infusion is added ad 100 ml of NaCl solution. What is the concentration (mg/ml) of the reconstituted solution for infusion?

To find the concentration of the reconstituted solution for infusion, we need to calculate the total amount of Nitro concentrate added to the NaCl solution and then divide it by the total volume.

1. The amount of Nitro concentrate added is 2 ml * 5 mg/ml = 10 mg.
2. The total volume of the reconstituted solution is 100 ml + 2 ml = 102 ml.
3. The concentration of the reconstituted solution is the total amount of Nitro concentrate (in mg) divided by the total volume (in ml):
Concentration = 10 mg / 102 ml = \frac{10}{102} mg/ml \approx 0.098 mg/ml.

Therefore, the concentration of the reconstituted solution for infusion is approximately 0.098 mg/ml.

\boxed{0.098 \, \text{mg/ml}}