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=
![\dfrac{[H^{+}] [A^{-}]}{[HA]}](https://tex.z-dn.net/?f=%5Cdfrac%7B%5BH%5E%7B%2B%7D%5D%20%5BA%5E%7B-%7D%5D%7D%7B%5BHA%5D%7D)
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Explanation:
- When an aqueous solution of a certain acid is prepared it is dissociated is as follows-
⇄ 
Here HA is a protonic acid such as acetic acid, 
- The double arrow signifies that it is an equilibrium process, which means the dissociation and recombination of the acid occur simultaneously.
- The acid dissociation constant can be given by -
= ![\dfrac{[H^{+}] [A^{-}]}{[HA]}](https://tex.z-dn.net/?f=%5Cdfrac%7B%5BH%5E%7B%2B%7D%5D%20%5BA%5E%7B-%7D%5D%7D%7B%5BHA%5D%7D)
- The reaction is can also be represented by Bronsted and lowry -
⇄ ![[H_3O^+] [A^-]](https://tex.z-dn.net/?f=%5BH_3O%5E%2B%5D%20%5BA%5E-%5D)
- Then the dissociation constant will be
= ![\dfrac{[H_3O^{+}] [A^{-}]}{[HA]}](https://tex.z-dn.net/?f=%5Cdfrac%7B%5BH_3O%5E%7B%2B%7D%5D%20%5BA%5E%7B-%7D%5D%7D%7B%5BHA%5D%7D)
Here,
is the dissociation constant of an acid.
Answer: weigh is m = n × M = 2.87 mol × 58.44 g/mol
Explanation: mass = amount of substance × molar mass
M((NaCl) = 22.99 +35.45