0.30M nh3 and 0.20M HCL calculate the ph of solution kb=1.8 × 10^-5
To calculate the pH of a solution, we need to determine the concentration of H+ ions in the solution. In this case, we have ammonia (NH3) and hydrochloric acid (HCl) reacting in a solution.
NH3 + HCl → NH4+ + Cl-
Since NH4+ is a weak acid, it can undergo partial dissociation in water, generating H+ ions. Therefore, we need to calculate the concentration of NH4+ ions to determine the concentration of H+ ions.
Let's denote the initial concentration of NH3 as [NH3]0 and the concentration of NH4+ as [NH4+]. The reaction will consume NH3 and generate NH4+ in the same molar ratio.
First, we'll calculate the concentration of NH4+:
[NH4+] = [NH3]0 - [NH3] (since it is a weak acid, [NH4+] = [NH3]0 - [NH3])
Given that the initial concentration of NH3 is 0.30 M, we substitute it into the equation:
[NH4+] = 0.30 M - [NH3]
Now, we need to determine the concentration of H+ ions from the dissociation of NH4+.
The dissociation constant for NH4+ (Ka) can be calculated using the equilibrium expression:
Ka = [H+][NH3] / [NH4+]
Since we are asked to find the pH, which represents the negative logarithm of the H+ concentration, we can use Ka to find the concentration of H+ ions:
[H+] = sqrt(Ka * [NH4+])
Now, let's calculate Ka:
Ka = Kw / Kb
Kw is the ion product of water, which is 1.0 x 10^-14 at 25°C. Given that Kb is 1.8 x 10^-5, we can calculate Ka:
Ka = 1.0 x 10^-14 / 1.8 x 10^-5
Next, substitute the value of Ka and the concentration of NH4+ into the equation to find [H+]:
[H+] = sqrt(Ka * [NH4+])
Finally, you can take the negative logarithm of [H+] to obtain the pH:
pH = -log10([H+])
By following these steps, you should be able to calculate the pH of the solution.