Question

How many mL of 0.45 M HCl must be added to 25.0 mL of 1.00 M KOH to make a neutral solution?

A) 25.0 mL
B) 55.5 mL
C) 45.0 mL
D) 20.0 mL

Answer 1

To make a neutral solution, we need to have an equal number of moles of HCl and KOH. The volume of 0.45 M HCl needed is approximately 55.5 mL.

Step-by-step explanation:

To make a neutral solution, we need to have an equal number of moles of HCl and KOH. First, we can calculate the number of moles of KOH in the given 25.0 mL solution:

Moles of KOH = volume (L) x concentration (M)

Moles of KOH = (25.0 mL / 1000 mL/L) x 1.00 M = 0.025 moles

Since the ratio of HCl to KOH is 1:1, we need 0.025 moles of HCl to neutralize the solution. We can calculate the volume of 0.45 M HCl needed using the formula:

Volume (mL) = moles / concentration

Volume (mL) = 0.025 moles / 0.45 M = 0.0556 mL ≈ 55.5 mL