An aqueous solution of calcium hydroxide is standardized by titration with a 0.183 M solution of hydrochloric acid. If 16.6 mL of base are required to neutralize 25.8 mL of the acid, what is the molarity of the calcium hydroxide solution?

Molarity of calcium hydroxide (C1) = ?

Molarity of hydrochloric acid (C2) = 0.183 M

Volume of hydrochloric acid (V2) = 25.8 ml

Volume of calcium hydroxide (V1) = 16.6 ml

Using the equation of

C1*V1 = C2*V2

C2 = 0.183 * 25.8/16.6

C2 = 0.284 M

The molarity of calcium hydroxide is 0.284 M

0.142 M

Explanation:

Let's consider the neutralization reaction between calcium hydroxide and hydrochloric acid.

Ca (OH) ₂ + 2 HCl → CaCl₂ + 2 H₂O

25.8 mL of 0.183 M HCl are used. The reacting moles are:

0.0258 L * 0.183 mol/L = 4.72 * 10⁻³ mol

The molar ratio of Ca (OH) ₂ to HCl is 1:2. The reacting moles of Ca (OH) ₂ are 1/2 * 4.72 * 10⁻³ mol = 2.36 * 10⁻³ mol

2.36 * 10⁻³ moles of Ca (OH) ₂ are contained in 16.6 mL. The molarity of Ca (OH) ₂ is:

M = 2.36 * 10⁻³ mol/0.0166 L = 0.142 M