Ph of HCL and dissociationdegree pleasse help?

2016-08-02 7:30 pm

Calculate the pH of an HCl solution 0,30M
a) assuming that dissociation degree = 1

b) assuming that degree of dissociation = 0.88

How to solve if there's dissociatie degree given ? what has dissociatie degree to do with ph ?? How does ph change ??? please explain thank you

回答 (1)

戇戇居士

2016-08-02 7:39 pm

✔ 最佳答案

The dissociation degree of HCl is the fraction that the acid molecules dissociates to H₃O⁺ ions. The greater the dissociation degree, the higher the [H₃O⁺] is.
As pH = -log[H₃O⁺], the higher the [H₃O⁺], the lower the pH is.
Hence, the greater the dissociation degree of an acid, the lower the pH is.

a)
When dissociation degree = 1
[H₃O⁺] = (0.30 M) × 1 = 0.30 M
pH = -log[H₃O⁺] = -log(0.30) = 0.52

b)
When dissociation degree = 0.88
[H₃O⁺] = 0.30 × 0.88 M
pH = -log[H₃O⁺] = -log(0.30 × 0.88) = 0.58

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