# Question #2b095

##### 1 Answer

**!! LONG ANSWER !!**

You'd need **30 mL** of hydrochloric acid solution to get the pH to that value.

So, you know that you're dealing with a potassium hydroxide solution. Since potassium hydroxide is *strong base*, it dissociates completely in aqueous solution to give potassium cations,

The

Use the volume of the solution to determine how many moles of hydroxide ions are present

This means that, in order to get a *neutral solution*, you need to add **0.001 moles** of hydrochloric acid. This much acid will completely neutralize the initial solution and get it to a pH of **7**.

Figure out how much volume of hydrochloric acid solution is needed to neutralize the potassium hydroxide solution

However, you want the final solution to be *acidic*, which implies that you need an excess of

Use the final solution's pH to determine what the concentration of the hydronium ions must be in order for the solution to have pH of **2**

Now you need to determine how much

Think of it like this. After neutralization, the number of moles of hydrochloric acid present in what you *add* must be **equal to** the number of moles of hydrochloric acid that you're *left with*.

In other words, you need to *dilute* a sample of

**after the initial solution was neutralized**;

**total** volume of the final solution.

But

This means that you get

Therefore, the **total** volume of