Butyric acid, the compound responsible for the unpleasant odor and taste of sour milk, has a pK_a value of 4.82. What is its K_a value? Is it a stronger acid or a weaker acid than vitamin C?

K_a is defined as the dissociation constant of an acid. The more is the release of H⁺ in solution, the more will be the dissociation Constant and the acidity of the solution.

pK_a if given as the negative logarithmic value of acid dissociation constant (K_a). It is given as,

pK_a= - log (K_a)

The more is the acid dissociation constant or the acidity of a compound, the less will be the pK_a value.

Here, the pK_a value of butyric acid is =4.82.

The K_avalue is = 10^-4.82=1.51 x 10^-5

Vitamin C has two pK_a values for two acid dissociation constants and they are 4.10 and 11.6. So, if we compare butyric acid with pK_a value of ascorbic acid, the later will be more acidic and if the butyric acid is compared with 2^nd pK_a of ascorbic acid, the former will be more acidic.