Sodium fluoride is added to many municipal water supplies to reduce tooth decay. Calculate the pH of a 3.39×10-3 M solution of NaF, given that the Ka of HF = 6.80 x 10-4 at 25°C.
Ionic Equilibrium
Chemical equilibrium and ionic equilibrium are two major concepts in chemistry. Ionic equilibrium deals with the equilibrium involved in an ionization process while chemical equilibrium deals with the equilibrium during a chemical change. Ionic equilibrium is established between the ions and unionized species in a system. Understanding the concept of ionic equilibrium is very important to answer the questions related to certain chemical reactions in chemistry.
Arrhenius Acid
Arrhenius acid act as a good electrolyte as it dissociates to its respective ions in the aqueous solutions. Keeping it similar to the general acid properties, Arrhenius acid also neutralizes bases and turns litmus paper into red.
Bronsted Lowry Base In Inorganic Chemistry
Bronsted-Lowry base in inorganic chemistry is any chemical substance that can accept a proton from the other chemical substance it is reacting with.
The dissociation of NaF is given as-
The concentration of NaF,
Ka of HF = 6.80 x 10-4
As the reaction happens in an aqueous medium the water molecules dissociate in the form-
Na+ only reacts with OH- ions in the reaction mixture which is a strong base and dissociates completely and will not hydrolyze, whereas on the other hand, F- can only react with H+ ions and form HF which is a weak acid and will hydrolyze. The equation for the hydrolysis is given as-
As the conc. of F- is the same as that of NaF given because NaF dissociates completely in the aqueous solution. So, the hydrolysis equation is an equilibrium equation which means not all F- gives HF but the pH is given by the concentration of OH- ions in the solution which is given as-
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