Explanation

Using the neutralization formula:
M₁V₁ = M₂V₂

Given:

• M₁ (HCl) = 0.50 M
• V₁ (HCl) = 10 mL
• M₂ (NaOH) = 0.25 M
• V₂ (NaOH) = ?

Now, solving:
(0.50 M) (10 mL) = (0.25 M) (V₂)
5 = 0.25V₂
V₂ = 20 mL