4 Acids Bases

Question 1

Definition of an acid:

Answer 1

An acid is any compound capable of donating a proton (hydrogen), H+.

Question 2

Definition of a base:

Answer 2

A base is any substance that is capable of accepting a proton (hydrogen ion), H+.

Question 3

Acids that can ONLY donate one proton are…

Answer 3

Monoprotic.

Question 4

Acids that can donate 2 protons are…

Answer 4

Diprotic.

Question 5

Acids that can donate 3 protons are…

Answer 5

Triprotic.

Question 6

Polyprotic acids are…

Answer 6

Acids that can donate more than 1 proton.

Question 7

What happens as polyprotic acids donate consecutive protons?

Answer 7

As polyprotic acids donate consecutive protons, they become more negatively charged, and less likely to ionise.

Question 8

List the properties of a strong acid (extent of dissociation, reaction with water and conductivity etc.)

Answer 8

• Higher ion concentration equals greater conductivity
• Strong acids completely ionise. Each molecule reacts with water to ionise to form a H+ ion. They typically have a full 100% dissociation.
• Strong acids react quickly with water to ionise. All the acid molecules dissociate to form ions.

Question 9

List the properties of a weak acid (extent of dissociation, reaction with water and electrical conductivity etc.)

Answer 9

• Weak acids typically do not have a vigorous reaction with water
• Weak acids only partially ionise –> they are a reversible reaction so they exist as an equilibrium
• Weak acids do not dissociate easily, and so overall ion concentration is low, hence conductivity is low
• Only a small proportion of acid molecules ionise. Their extent of ionisation is low.

Question 10

Are STRONG and WEAK the same as CONCENTRATED and DILUTE?

Answer 10

STRONG and WEAK are not the same as CONCENTRATED and DILUTE. When a strong acid and a weak acid have the same concentration, they strong acid will have a much lower pH, and a much higher conductivity.