Answer:
the sodium hydroxide solution was 0.4 M.
Step-by-step explanation:
To solve this problem, we can use the dilution formula:
M1V1 = M2V2
where M1 is the initial concentration, V1 is the initial volume, M2 is the final concentration, and V2 is the final volume.
We are given that 45.0 mL of a sodium hydroxide solution was diluted and the resulting volume is 180 mL with a concentration of 0.100 M. Let's use M1 for the initial concentration, V1 for the initial volume, M2 for the final concentration, and V2 for the final volume.
M2 = 0.100 M
V1 = 45.0 mL
V2 = 180 mL
We can rearrange the dilution formula to solve for M1:
M1 = (M2V2) / V1
Substituting the given values, we get:
M1 = (0.100 M x 180 mL) / 45.0 mL
M1 = 0.400 M
Therefore, the initial molarity of the sodium hydroxide solution was 0.4 M.