Question

If 20.0mL of a 0.500M HCl solution is required to neutralize 35.0mL KOH, what is the concentration of the KOH solution?

A) 0.286M
B) 0.572M
C)1.00M
D) 1.14M

Answer 1

The concentration of the KOH solution is determined by stoichiometry and the fact that neutralization reactions have a 1:1 ratio of acid to base. By calculating the moles of HCl used and knowing the volume of KOH solution, we find the concentration of KOH to be 0.286M.

Step-by-step explanation:

To determine the concentration of the KOH solution, we can apply the concept of stoichiometry in a neutralization reaction. First, we compare the moles of HCl used to the moles of KOH that need to be neutralized, which according to the balanced chemical equation is a 1:1 ratio since HCl and KOH dissociate into one equivalent of H+ and OH- ions, respectively.

Calculating the moles of HCl used:
Moles of HCl = volume (L) × concentration (M)Moles of HCl = 0.0200 L × 0.500 M = 0.0100 mol

Since the reaction ratio is 1:1, the moles of KOH must also be 0.0100 mol. Now, we can calculate the molarity of the KOH solution:

Concentration of KOH = moles of KOH / volume of KOH solution in liters

Concentration of KOH = 0.0100 mol / 0.0350 L = 0.286 M

Therefore, the correct answer is A) 0.286M.