Answer:
0.80 M
Explanation:
Step 1: Write the generic neutralization reaction
HA + NaOH ⇒ NaA + H₂O
Step 2: Calculate the reacting moles of NaOH
20.05 mL of 1.000 M NaOH react.
0.02005 L × 1.000 mol/L = 0.02005 mol
Step 3: Calculate the reacting moles of HA
The molar ratio of NaOH to HA is 1:1. The reacting moles of HA is 1/1 × 0.02005 mol = 0.02005 mol.
Step 4: Calculate the concentration of HA
0.02005 moles of HA are in 25 mL.
[HA] = 0.02005 mol/0.025 L = 0.80 M