1. Moles of NaCl in the Initial Solution:
* Moles = Concentration (mol/L) x Volume (L)
* Moles of NaCl = 0.200 mol/L * 0.100 L = 0.020 moles NaCl
2. Moles of Cl- Ions:
* Since NaCl dissociates into one Na+ ion and one Cl- ion, the moles of Cl- ions are equal to the moles of NaCl.
* Moles of Cl- = 0.020 moles
3. Total Volume of the Solution:
* Total volume = 100 mL + 400 mL = 500 mL = 0.500 L
4. Concentration of Cl- Ions:
* Concentration = Moles / Volume
* Concentration of Cl- = 0.020 moles / 0.500 L = 0.040 mol/L
Therefore, the concentration of Cl- ions in the resulting solution is 0.040 mol/L.
