Question

Определите pH 0.02н. раствора дихромовой кислоты, если степень диссоциации ее 50%. Ответ: 2

Answer 1

Если степень диссоциации 50% то только половина всех молекул кислоты продиссоциирует, то есть концентрация будет 0,01 н. 
pH = -lg(0,01) = 2

Answer 2

Вычисляем концентрацию продиссоциирующих молекул:
n=N*α
n=0.02 моль/л*0,5 = 0,01 моль/л
рН = -lg(0.01) = 2

Answer 3

Determining the pH of a 0.02 M Solution of Dichromic Acid with 50% Dissociation

To determine the pH of a solution, we need to consider the concentration of hydrogen ions (H+) in the solution. In the case of an acid, the higher the concentration of H+ ions, the lower the pH value.

Given that the degree of dissociation of dichromic acid is 50%, we can assume that half of the acid molecules have dissociated into H+ ions and dichromate ions (Cr2O7^2-). Therefore, the concentration of H+ ions in the solution is half of the initial concentration of the acid.

The initial concentration of the dichromic acid is 0.02 M. Since the degree of dissociation is 50%, the concentration of H+ ions is 0.02 M / 2 = 0.01 M.

Now, let's determine the pH of the solution using the concentration of H+ ions.

The pH scale is a logarithmic scale that measures the acidity or alkalinity of a solution. The pH is defined as the negative logarithm (base 10) of the concentration of H+ ions.

Using the concentration of H+ ions in the solution (0.01 M), we can calculate the pH as follows:

pH = -log[H+]

pH = -log(0.01)

Using a calculator, we find that the pH of the 0.02 M solution of dichromic acid with 50% dissociation is approximately 2.

Please note that the pH value is an approximation and may vary depending on the specific conditions and properties of the solution.

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