Question

Question #b984a

Answer 1

They would be acids.

Explanation:

Most substances that dissociate into constituent ions in aqueous solution are ionic compounds (`"KCl"`, `"NaBr"`, `"AlCl"_3`, etc.). These solvated ions carry a current between electrodes and conduct electricity.

However, there some very important covalent compounds that dissociate as well, and they are called acids.

Acids have a few different definitions, but they can be categorized into two main groups: strong acids and weak acids.

Strong acids are those that dissociate essentially completely in solution; i.e. there isn't really an equilibrium established between between the composite ions and the molecule itself. There are seven common strong acids:

• `"HCl"`

• `"HNO"_3`

• `"HBr"`

• `"HI"`

• `"HClO"_3`

• `"HClO"_4`

• `"H"_2"SO"_4`

(notice there is only one diprotic acid: sulfuric acid)

Weak acids essentially consist of all acids that are not the above seven. They do not dissociate to near completion, and have a measurable equilibrium between molecule and dissociated ions.

Weak acids have an acid dissociation constant, denoted `K_a`, that describes the ratio of concentration of component ions to concentration of the whole molecule, and the value will always be less than `1` (with the exception of the hydronium ion (`"H"_3"O"^+`), whose value is `1`).

For example, for the weak acid `"HF"`, we have the equilibrium expression

`K_a = (["H"^+]["F"^-])/(["HF"])`

The `K_a` value for hydrofluoric acid is `7.2xx10^-4`, which indicates the concentration of `"HF"` is greater than that of `"H"^+` and `"F"^-`; i.e. the equilibrium lies to the left.