Hydrochloric acid (HCl) is commonly sold as a pool additive, where it is used to lower the pH of the pool water if it is too high. Swimming pools are commonly kept between a pH of 7.0 - 7.6 to ensure the comfort of the swimmers. You find a bottle of HCl in the pool aisle at the hardware store which is labelled as having a concentration of 192 g/L. What is the pH of this solution, to 2 decimal places? The molar mass of HCl is 36.46 g/mol.Remember: pH = -log10[H3O+(aq)], pOH = -log10[OH-(aq)] and pH + pOH = 14.00

To find the pH of the solution, we first need to find the concentration of HCl in moles per liter (M).

1. Convert the concentration from g/L to mol/L.

Given that the molar mass of HCl is 36.46 g/mol, we can use this to convert the concentration:

192 g/L ÷ 36.46 g/mol = 5.27 mol/L

So, the concentration of HCl is 5.27 M.

2. Calculate the pH.

The pH is calculated using the formula pH = -log10[H3O+(aq)]. In a solution of a strong acid like HCl, the concentration of H3O+ ions is equal to the concentration of the acid. Therefore, we can substitute the concentration of HCl into the formula:

pH = -log10[5.27] = -0.72

However, pH is a measure of acidity and cannot be negative. The negative value indicates that the solution is extremely acidic. In practice, pH values are often reported as positive values, so we would report the pH of this solution as 0.72.

Please note that this is a theoretical calculation. In reality, the pH of a solution cannot be less than 0. The negative value simply indicates that the solution is very acidic.