Answer:
The pH of the resulting hydrochloric acid solution is 1.896
Explanation:
pH, short for Hydrogen Potential, is a measure of acidity or alkalinity that indicates the amount of hydrogen ions present in a solution or substance.
The pH scale goes from 0 to 14. Values less than 7 indicate the range of acidity and those greater than 7 indicate alkalinity or basicity. The value 7 is considered neutral.
pH is defined as the opposite of the base 10 logarithm or the negative logarithm of the activity of hydrogen ions or hydronium ions (H₃O)., whose equation is
pH = -log [H⁺] = -log[H₃O⁺]
Then you must know the concentration of [H⁺] or [H₃O⁺]
A strong acid is one that dissociates completely, therefore, a quantity of H + ions are transferred to the solution. Since HCl is a strong acid, then [HCl] = [H⁺]
Being molarity the number of moles of solute that are dissolved in a certain volume, it is defined as:
[tex]molarity=\frac{moles of solute}{volume}[/tex]
So you must know the number of moles of HCl. Being its molar mass equal to 36.45 [tex]\frac{g}{mole}[/tex], then the following rule of three can be applied: if there are 35.45 grams of HCl in 1 mole, 0.9 grams of HCl in how many moles will they be?
[tex]moles of HCl=\frac{0.9 grams*1 mole}{35.45 grams}[/tex]
moles of HCl= 0.0254
Then, being the number of moles of solute 0.0254 and the volume 2 L, the molarity is:
[tex]molarity=\frac{0.0254 moles}{2 L}[/tex]
[tex]molarity=0.0127\frac{moles}{L}[/tex]
Then, the concentration of [HCl] is 0.0127 [tex]\frac{moles}{L}[/tex]. So [HCl] = [H⁺] = 0.0127 [tex]\frac{moles}{L}[/tex].
So the pH is calculated as:
pH = -log [H⁺]= -log 0.0127
pH= 1.896
The pH of the resulting hydrochloric acid solution is 1.896
