Acid-Base Reactions
Introduced| English |
|---|
| acid/ˈæsɪd/ |
| base/beɪs/ |
| neutralization/ˌnjuːtrəlaɪˈzeɪʃn/ |
The great proton handoff
- Lemon juice stings; soap feels slippery.
- One eagerly gives away a tiny particle; the other grabs it.
- Mix them and they cancel each other out.
- A single proton passed along explains it all.
Donors and acceptors
- An acid 酸 donates a hydrogen ion ($\text{H}^+$, a proton).
- A base 碱 accepts that hydrogen ion.
- This is the Bronsted-Lowry picture.
In the Bronsted-Lowry model, an acid is a substance that...
An acid is a proton donor; a base is a proton acceptor.
A base is a proton ____.
A base accepts the proton the acid donates.
Neutralization
- Neutralization 中和 is an acid reacting with a base.
- The products are a salt and water.
- $\text{HCl} + \text{NaOH} \to \text{NaCl} + \text{H}_2\text{O}$.
Neutralizing an acid with a base produces...
Acid + base gives a salt plus water.
Strong and weak
- A strong acid or base ionizes completely in water.
- A weak one only partly ionizes.
- Strength is about how fully it dissociates, not how concentrated it is.
Acid or base?
In each reaction, decide which species donates a proton (acid) and which accepts one (base).
A strong acid is always more concentrated than a weak acid.
Strength (ionization) is independent of concentration.
A strong acid ionizes completely in water.
Complete ionization is exactly what "strong" means.
What forms when $\text{HCl}$ reacts with $\text{NaOH}$?
- The $\text{H}^+$ and $\text{OH}^-$ join to make water.
- The leftover $\text{Na}^+$ and $\text{Cl}^-$ make the salt $\text{NaCl}$.
When $\text{H}^+$ meets $\text{OH}^-$ in neutralization, they form...
$\text{H}^+ + \text{OH}^- \to \text{H}_2\text{O}$.
Do not confuse strength with concentration -- a strong acid can be dilute, and a weak acid can be concentrated. Strong means fully ionized. Neutralization always yields a salt plus water. And the acid donates the proton while the base accepts it.
An acid donates a proton ($\text{H}^+$) and a base accepts one. Their neutralization produces a salt and water, like $\text{HCl} + \text{NaOH} \to \text{NaCl} + \text{H}_2\text{O}$. Strength (fully vs partly ionized) is separate from concentration.