Final answer:
The mass of NaCl in the solution is 104.16 g.
Step-by-step explanation:
To calculate the mass of NaCl, we need to consider the concentration of the NaCl solution and its density. From the given information, the total volume of HCl plus NaOH solutions is 100.1 mL. Assuming 1 M NaCl has a density of 1.04 g/mL, we can calculate the mass of NaCl.
The volume of the NaCl solution is 100.1 mL, and its density is 1.04 g/mL, so the mass of the NaCl solution is 100.1 mL * 1.04 g/mL = 104.16 g.
Therefore, the mass of NaCl is 104.16 g.