Answer:
0.456 M
Explanation:
Step 1: Write the balanced neutralization equation
HNO₂ + KOH ⇒ KNO₂ + H₂O
Step 2: Calculate the reacting moles of KOH
9.26 mL of 1.235 M KOH react.
0.00926 L × 1.235 mol/L = 0.0114 mol
Step 3: Calculate the reacting moles of HNO₂
The molar ratio of HNO₂ to KOH is 1:1. The reacting moles of HNO₂ are 1/1 × 0.0114 mol = 0.0114 mol.
Step 4: Calculate the initial concentration of HNO₂
0.0114 moles of HNO₂ are in 25.0 mL of solution.
[HNO₂] = 0.0114 mol / 0.0250 L = 0.456 M
