Question

0.50 g of hydrogen chloride (HCl) is dissolved in water to make 4.0 L of solution. What is the pH of the resulting hydrochloric acid solution

Answer 1

Step-by-step explanation:

Given the mass of HCl is ---- 0.50 g

The volume of solution is --- 4.0 L

To determine the pH of the resulting solution, follow the below-shown procedure:

1. Calculate the number of moles of HCl given by using the formula:

`number of moles of a substance=(given mass of the substance)/(its molecular mass)`

2. Calculate the molarity of HCl.

3. Calculate pH of the solution using the formula:

`pH=-log[H^+]`

Since HCl is a strong acid, it undergoes complete ionization when dissolved in water.

`HCl(aq)->H^+(aq)+Cl^-(aq)`

Thus,
`[HCl]=[H^+]`

Calculation:

1. Number of moles of HCl given:

`number of moles of a substance=(given mass of the substance)/(its molecular mass)\\=0.50g/36.5g/mol\\=0.0137mol`

2. Concentration of HCl:

`Molarity of HCl=(number of moles of HCl)/(its molar mass)\\=(0.0137 mol)/(4.0 L) \\= 0.003425 M`

3. pH of the solution:

`pH=-log[H^+]\\=-log(0.003425)\\=2.47`

Hence, pH of the given solution is 2.47.