Question

Помогите пожалуйста 1)pH 0,05 М раствора соли CH3COONa равен: 5; 10; 8,73; 12. 2).Константа гидролиза 0,04 М раствора соли NH4NO3 равна 2х10-10; 0,1х10-5; 5,59х10-10; 1х10-2 .

Answer 1

Ответ:

1) pH = 7 + 1/2pKa + 1/2Ig C

pH = 7 + 1/2 * 4.75 + 1/2Ig 0.05

pH = 8,73

2)Kг = K(H2O)/K(NH4OH) = 10^(-14)/1.8*10^(-5)

Кг = 5,59*10^(-10)

Объяснение:

Answer 2

pH of a solution of CH3COONa:

The pH of a solution of CH3COONa can be determined by considering the hydrolysis of the salt. CH3COONa is the sodium salt of acetic acid (CH3COOH). When this salt dissolves in water, it undergoes hydrolysis, resulting in the formation of acetic acid and sodium hydroxide. The acetic acid can then donate a proton (H+) to water, leading to the formation of hydronium ions (H3O+). The concentration of hydronium ions determines the pH of the solution.

To calculate the pH of the solution, we need to consider the dissociation of acetic acid and the concentration of hydronium ions. The dissociation constant of acetic acid (Ka) is 1.8 x 10^-5 at 25°C. The concentration of acetic acid in the solution is determined by the concentration of the salt CH3COONa.

The pH of the solution can be calculated using the equation:

pH = -log[H3O+]

To find the concentration of hydronium ions, we need to consider the dissociation of acetic acid. The concentration of acetic acid can be calculated using the equation:

[H3O+] = √(Ka * [CH3COONa])

Let's calculate the pH of the solution using the given concentration of the salt CH3COONa.

Given: Concentration of the salt CH3COONa = 0.05 M

Using the equation above, we can calculate the concentration of hydronium ions:

[H3O+] = √(1.8 x 10^-5 * 0.05) = 3 x 10^-4 M

Now, we can calculate the pH using the concentration of hydronium ions:

pH = -log(3 x 10^-4) ≈ 3.52

Therefore, the pH of a 0.05 M solution of CH3COONa is approximately 3.52.

Hydrolysis constant of NH4NO3:

The hydrolysis constant of a salt indicates the extent to which it undergoes hydrolysis in water. In the case of NH4NO3, the salt is the ammonium salt of nitric acid. When NH4NO3 dissolves in water, it undergoes hydrolysis, resulting in the formation of ammonium ions (NH4+) and nitrate ions (NO3-). The ammonium ions can then react with water, leading to the formation of hydronium ions (H3O+). The concentration of hydronium ions determines the pH of the solution.

The hydrolysis constant (Kh) of NH4NO3 can be calculated using the equation:

Kh = [NH4+][OH-] / [NH4NO3]

The concentration of hydroxide ions (OH-) can be determined by the concentration of hydronium ions (H3O+) using the equation:

[H3O+][OH-] = Kw = 1.0 x 10^-14

Given: Concentration of the salt NH4NO3 = 0.04 M

Using the equation above, we can calculate the hydrolysis constant:

Kh = [NH4+][OH-] / [NH4NO3] = (x)(x) / 0.04 = x^2 / 0.04

Since the concentration of hydroxide ions is equal to the concentration of hydronium ions in water, we can substitute [OH-] with [H3O+]:

Kh = (x)(x) / 0.04 = x^2 / 0.04 = (1.0 x 10^-14) / 0.04

Solving for x, we find:

x ≈ 5.0 x 10^-10

Therefore, the hydrolysis constant of a 0.04 M solution of NH4NO3 is approximately 5.0 x 10^-10.