Find the volume of a 20% KOH solution with a density of 1.1 g / cm₃, which is required to neutralize 4.6 g of formic acid.

#1. Let’s write the reaction equation:

KOH + HCOOH → HCOOK + H2O

# 2. Find the amount of acid:

n (HCOOH) = m (HCOOH) / Mr (HCOOH) = 4.6 / 46 = 0.1 mol;

# 3. Let’s find the mass of KOH:

n (KOH) = n (HCOOH) = 0.1 mol;

m (KOH) = n (KOH) * Mr (KOH) = 0.1 * 56 = 5.6 g.

#4. Let’s find the volume of the solution:

m (p-pa) = m (KOH) / ω (KOH) = 5.6 / 0.2 = 28 g.

V (p-pa) = m (p-pa) / ρ (p-pa) = 28 / 1.1 = 25.45 ml.

Answer: 25.45 ml.