A chemist dissolves 156mg of pure hydrobromic acid in enough water to make up 220mL of solution. Calculate the pH of the solution. Be sure your answer has the correct number of significant digits.

Answer : The pH of the solution is, 2.06

Explanation : Given,

Mass of HBr = 156 mg = 0.156 g   (1 mg = 0.001 g)

Volume of solution = 220 mL

Molar mass of HBr = 80.9 g/mol

First we have to calculate the molarity or concentration of HBr.

Molarity : It is defined as the number of moles of solute present in one liter of volume of solution.

Formula used :

Now put all the given values in this formula, we get:

As 1 mole of HBr dissociates to give 1 mole of hydrogen ion and 1 mole of bromide ion.

So, 0.00876 M of HBr dissociates to give 0.00876 M of hydrogen ion and 0.00876 M of bromide ion.

Now we have to calculate the pH of the solution.

Thus, the pH of the solution is, 2.06