Calculate the pH of a 0.052 NH4Cl aqueous solution
This is a hydrolysis equation.
NH4^+ + H2O ==> NH3 + H3O^+
Ka = (Kw/Kb) = (NH3)(H3O^+)/(NH4^+)
Set up an ICE chart, substitute, solve for H3O^+ and convert to pH.
To calculate the pH of a solution, you need to consider the dissociation of the solute NH4Cl in water. NH4Cl is a salt, which means it dissociates into ions when dissolved in water.
The dissociation of NH4Cl can be represented as follows:
NH4Cl -> NH4+ + Cl-
Since NH4Cl is a strong acid, it completely dissociates in water. NH4+ is the conjugate acid of the weak base NH3 (ammonia), while Cl- is a neutral spectator ion.
When NH4+ dissolves in water, it can also act as an acid and donate a proton (H+) to water, resulting in the formation of H3O+ ions (hydronium ions) in the solution.
NH4+ + H2O -> NH3 + H3O+
The concentration of NH4Cl is given as 0.052 M. Since NH4Cl dissociates into one NH4+ ion and one Cl- ion, both the NH4+ and Cl- ions will have a concentration of 0.052 M.
Now, to calculate the pH of the solution, we need to determine the concentration of H3O+ ions. Since NH4+ acts as an acid and donates a proton to water, the concentration of H3O+ ions will be the same as the concentration of NH4+ ions.
Therefore, the concentration of H3O+ ions in the solution is 0.052 M.
The pH of a solution can be calculated using the formula:
pH = -log[H3O+]
Substituting the value of [H3O+], we get:
pH = -log(0.052)
Using a scientific calculator, evaluate -log(0.052) to get the pH value.
Note: The concentration of H3O+ ions is considered to be equal to the concentration of NH4+ ions due to the complete dissociation of NH4Cl in water. This assumption holds true because NH4+ is a strong acid and fully dissociates in aqueous solution.