Answer:
A) 0.1225 M
B) 100.4 g/mol
Explanation:
Step 1: Write the generic neutralization reaction
HA(aq) + NaOH(aq) ⇒ NaA(aq) + H₂O(l)
Step 2: Calculate the reacting moles of NaOH
17.73 mL of 0.1036 M NaOH react. The reacting moles are:
0.01773 L × 0.1036 mol/L = 1.837 × 10⁻³ mol
Step 3: Calculate the reacting moles of HA
The molar ratio of HA to NaOH is 1:1. The reacting moles of HA are 1/1 × 1.837 × 10⁻³ mol = 1.837 × 10⁻³ mol.
Step 4: Calculate the molar concentration of HA
1.837 × 10⁻³ moles of HA are in a 15.00 mL volume. The molar concentration is:
M = 1.837 × 10⁻³ mol / 0.01500 L = 0.1225 M
Step 5: Calculate the molar mass of HA
1.837 × 10⁻³ moles of HA weigh 0.1845 g. The molar mass of HA is:
0.1845 g / 1.837 × 10⁻³ mol = 100.4 g/mol
