We can talk about the acids and bases using the pH scale at room temperature which goes from 0 to 14.
A neutral solution has pH of 7. The hydrogen ion concentration of a neutral solution can be found by using `k_w` , the dissassociation constant of water.
`k_w = [H^+][OH^-]`
At room temperature, `k_w = 1 xx 10^(-14) mol^2dm^(-6)`
In a neutral solution `[H^+] = [OH^-]` . Therefore,
`[H^+] = [OH^-] = 1 xx 10^(-7) moldm^(-3)`
Acids have a pH lower than 7. Depending on how low the number is acids are catgorised into weak acids and strong acids. The hydrogen ion concentration of acids is higher than `1 xx 10^(-7)` and hydroxyl ion concentation is lower than `1 xx 10^(-7)` .
For example: An acid with pH of 3 will have,
`[H^+] = 1 xx 10^(-4)`
`[OH^-] = 1 xx 10^(-10)`
On the other hand, bases have pH higher than 7. Depending on how high the pH value is they are categorised into weak bases and strong bases.
For example: A base with pH value 10 would have,
`[H^+] = 1 xx 10^(-10)`
`[OH^-] = 1 xx 10^(-4)`
Due to this difference in H+ and OH- ions, acids and bases react differently to reactions. Acids react with metals and bases usually react with non-metals.