Answer:
4.21 M
Explanation:
Step 1: Write the balanced equation
NaOH + HCl ⇒ NaCl + H₂O
Step 2: Calculate the reacting moles of HCl
30.6 mL of 1.65 M HCl reacted. The reacting moles of HCl are:
[tex]0.0306 L \times \frac{1.65mol}{L} = 0.0505 mol[/tex]
Step 3: Calculate the reacting moles of NaOH
The molar ratio of NaOH to HCl is 1:1. The reacting moles of NaOH are 1/1 × 0.0505 mol = 0.0505 mol.
Step 4: Calculate the molar concentration of NaOH
0.0505 moles of NaOH are in 12.00 mL. The molar concentration of NaOH is:
[tex]M = \frac{0.0505 mol}{0.01200L} = 4.21 M[/tex]