Question

28.0 cm of 0.75 mol/dm³ hydrochloric acid was used to neutralize 40.0 cm of potassium hydroxide solution. What was the concentration of the potassium hydroxide solution?

Answer 1

To find the concentration of the potassium hydroxide (KOH) solution, we can use the chemical equation and the volume and concentration of the hydrochloric acid (HCl) solution. By calculating the moles of HCl used, we can determine the concentration of the KOH solution.

Step-by-step explanation:

To find the concentration of the potassium hydroxide (KOH) solution, we can use the chemical equation and the volume and concentration of the hydrochloric acid (HCl) solution. According to the equation:

2HCl (aq) + 2KOH (aq) --> K2SO4 (aq) + 2H2O (l)

we can see that 2 moles of HCl react with 2 moles of KOH to produce 1 mole of K2SO4. Using the given information, we can calculate the moles of HCl used:

Moles of HCl = (volume of HCl) x (concentration of HCl) = 28.0 cm3 x 0.75 mol/dm³ = 21.0 mol.

Since 2 moles of HCl react with 2 moles of KOH, the moles of KOH in the solution is also 21.0 mol. Now, we can calculate the concentration of the KOH solution:

Concentration of KOH = (moles of KOH) / (volume of KOH solution) = 21.0 mol / 40.0 cm³ = 0.525 mol/dm³.