a)predict whether a 2.0mol/L solution of ammonia chloride will be acidic basic or neutral
b) calculate the pH of a 0.20 mil/L solution of NH4Cl
You know it will be acidic because it hydrolyzes to give H3O^+.
Part a is a 2.0 M solution; part b is a 0.2 M solution.
....................NH4^+ + HOH ==> NH3 + H3O^+
I....................0.2M........................0............0
C......................-x..........................x............x
E...................0.2-x.........................x............x
Ka for NH4^+ = Kw/Kb for NH3 = (NH4^+)(H3O^+)/(NH4^+)
Plug the E line into the Ka expression and solve for H3O^+, then convert to pH. You should get in the neighborhood of 5 for the pH.
a) To predict whether a solution of ammonium chloride (NH4Cl) will be acidic, basic, or neutral, we need to consider the dissociation of the compound in water. Ammonium chloride is a salt composed of the ammonium ion (NH4+) and the chloride ion (Cl-).
The ammonium ion can act as a weak acid, and when dissolved in water, it can donate a proton (H+) to the solution. The chloride ion does not have any effect on the acidity or basicity of the solution.
Since ammonium ions can release protons into the solution, the solution will be acidic. This is because the presence of excess hydrogen ions (H+) makes a solution acidic.
b) To calculate the pH of a solution of NH4Cl, we need to consider the dissociation of the ammonium ion (NH4+) in water. The dissociation of ammonium ion into ammonia (NH3) and a proton (H+) is an acid-base reaction.
NH4+ + H2O ⇌ NH3 + H3O+
When ammonium ion dissolves, it acts as an acid and donates a proton (H+) to water, forming ammonia (NH3) and hydronium ion (H3O+). In this case, the concentration of NH4+ = 0.20 mol/L since it is from a 0.20 mol/L solution of NH4Cl.
To calculate the pH, we need to find the concentration of the hydronium ion (H3O+). Since the concentration of NH4+ is equal to the concentration of H3O+, the concentration of H3O+ is also 0.20 mol/L.
pH is defined as the negative logarithm of the hydronium ion concentration:
pH = -log10[H3O+]
Thus, pH = -log10(0.20) ≈ 0.70
Therefore, the pH of the 0.20 mol/L solution of NH4Cl is approximately 0.70.