Question

What is the concentration of a sodium hydroxide solution if 14.5 mL of it are exactly neutralized by 30.0 mL of a 0.500 M hydrochloric acid solution?

Answer 1

Answer:

1.03 M

Explanation:

Step 1: Write the balanced equation

NaOH + HCl ⇒ NaCl + H₂O

Step 2: Calculate the reacting moles of HCl

30.0 mL (0.0300 L) of 0.500 M HCl react.

0.0300 L × 0.500 mol/L = 0.0150 mol

Step 3: Calculate the moles of NaOH that react with 0.0150 moles of HCl

The molar ratio of NaOH to HCl is 1:1. The moles of NaOH that react are 1/1 × 0.0150 mol = 0.0150 mol.

Step 4: Calculate the molar concentration of NaOH

0.0150 moles of NaOH are in 14.5 mL (0.0145 L).

M = 0.0150 mol/0.0145 L = 1.03 M