Concentration (in g/mL) = mass (in g) / volume (in mL)
Given:
Mass of solute (1.98 g)
Volume of solution (50 mL)
Concentration = 1.98 g / 50 mL
Now, let's calculate the concentration:
Concentration = 1.98 g / 50 mL
Concentration = 0.0396 g/mL
So, the concentration of the stock solution is 0.0396 g/mL