Acids + Bases

Question 1

Arrhenius acid

Answer 1

An Arrhenius acid ionises in aqueous solution to produce hydrogen ions

Question 2

Arrhenius base

Answer 2

An Arrhenius base dissociates in aqeous solution, producing hydroxide ions

Question 3

pH scale

Answer 3

Is a measure of the hydrogen ion concentration, and it is an inverse logarithmic scale

Question 4

Ionic product of water

Answer 4

Product of hydrogen ion and hydroxide ion concentrations. 10^-14 at 298K

Question 5

Celcius to Kelvin

Answer 5

C + 273.15

Question 6

Strong acid

Answer 6

Completely ionizes in aqueous solution to form H⁺

Question 7

Weak acid

Answer 7

Partially ionizes in aqueous solution to form H⁺

Question 8

Strong Base

Answer 8

Dissociate fully in aqueous solution - group 1 and 2 hydroxides and oxides

Question 9

Weak Base

Answer 9

Dissociate partially in aqueous solution - NH ₃, soluble hydroxides, metal hydroxides, metal phosphates, carbonates, and hydrogen carbonates

Question 10

Alkali

Answer 10

Can neutralize acids, contain a hydroxide ion

Question 11

Stong

Answer 11

High proportion of substance forms ions in solution

Question 12

Concentrated

Answer 12

Large amount of solute per volume of solution

Question 13

Explain using equations how H₃PO₄ is triprotic

Answer 13

Phosphoric acid is a weak acid. A weak acid ionises partially in water to produce hydrogen ions, donating 3 hydrogen ions. 1 mol of phosphoric acid contains 3 mol of hydrogen ions.

• show the equations, making sure to use double arrows as it is a weak acid

Question 14

The students’ teacher was explaining that the pH scale is a measure of the concentration of hydrogen ions (H+) in a solution. One of the students asked, “According to the Arrhenius theory, if bases are substances that produce hydroxide ions in solution, how can their pH be measured?”
Briefly answer the student’s question.

Answer 14

• all aqueous solutions have some H+ present
  -bases contain very low concentrations of H+
  -a low H+ concentration corresponds to a high pH (also accept explanations involving the formula pH = -log [H+])

Question 15

Using collision theory, explain why lime with finer particles will neutralise acidified soil more quickly.

Answer 15

Finer particles of lime have a greater surface area to volume ratio compared to larger particles. This means more particles are exposed and available to react with the acidic components in the soil. This increase surface area leads to a higher frequency of collisions between lime particles and hydrogen ions in the solid. As per collision theory, a higher frequency of effective collisions increases the rate of reaction. Finer lime stone particles facilitate more frequent and effective collisions, resulting in a faster neutralization process