Calculate the number of moles of NaCI in 200.0 mL of a 0.25 M solution of NaCI.

To calculate the number of moles of NaCl in the solution, we first need to determine the number of moles of NaCl present in 200.0 mL of the solution.

The formula to calculate the number of moles is:
Number of moles = concentration (M) x volume (L)

Given:
Concentration of NaCl = 0.25 M
Volume = 200.0 mL = 0.200 L

Number of moles = 0.25 M x 0.200 L = 0.05 moles

Therefore, there are 0.05 moles of NaCl in 200.0 mL of a 0.25 M solution of NaCl.