Acids And Bases

Question 1

Conjugate acid

Answer 1

Species produced when a base gains a proton.

Question 2

Conjugate base

Answer 2

Species produced when an acid loses a proton

Question 3

Conjugate acid-base pair

Answer 3

Two species related to another by the presence of a hydrogen ion or its absence

Question 4

Amphoteric

Answer 4

Substance that can act as both an acid and a base

Question 5

Why should you not mix acid based cleaners with bleach based cleaners?

Answer 5

They produce toxic chlorine gas

Question 6

If [H+] = [OH-] what does it tell you about the pH of the solution?

Answer 6

It’s neutral

Question 7

Strong acid

Answer 7

Acid that fully dissociates in water

Question 8

Why does the expression for Kw not include the concentration for water?

Answer 8

So little water is ionised at any one time, that it’s concentration remains relatively constant.

Question 9

Why does the value of Kw increase as the temperature increases?

Answer 9

The forward reaction is endothermic, and absorbs the heat supplied to charge this reaction. As a result equilibrium moves the the left and Kw increases.

Question 10

Strong acid

Answer 10

Fully ionises in solution

E.g. HCl, H2SO4, HNO3

Question 11

Buffer solution

Answer 11

A solution which resits changes in pH when small quantities of an acid or an alkali are added to it.

Question 12

Acidic buffer

Answer 12

A buffer with a pH less than 7

Question 13

What a common acidic buffer solution?

Answer 13

Ethanoic acid and sodium ethanoate

Question 14

How would you change the pH of a buffer solution?

Answer 14

By changing the ratio of acid to salt or by choosing a different acid and specific salt

Question 15

How does an acidic buffer solution resist changes in pH when an acid is added?

Answer 15

The newly introduced H+ combine with the ethanoate ions to make enthanoic acid.
This moves the equilibrium position to the left.

Question 16

How does an acidic buffer solution resist changes in pH when an alkali is added?

Answer 16

1) removal by reacting with HA
This is more like to happen
pH unlikely to change

2) removal by reacting with H+
OH- combine with these to make water
However this moves equilibrium to the right in order to make up for lost H+

Question 17

In the acid dissociation constant, [H+] =

Answer 17

Ka x ([HA]/[A-])

Question 18

Why does the expression for Kw not include the concentration for water?

Answer 18

So little water is ionised at any one time, that it’s concentration remains relatively constant.

Question 19

Why does the value of Kw increase as the temperature increases?

Answer 19

The forward reaction is endothermic, and absorbs the heat supplied to charge this reaction. As a result equilibrium moves the the left and Kw increases.

Question 20

Strong acid

Answer 20

Fully ionises in solution

E.g. HCl, H2SO4, HNO3

Question 21

Buffer solution

Answer 21

A solution which resits changes in pH when small quantities of an acid or an alkali are added to it.

Question 22

Acidic buffer

Answer 22

A buffer with a pH less than 7

Question 23

What a common acidic buffer solution?

Answer 23

Ethanoic acid and sodium ethanoate

Question 24

How would you change the pH of a buffer solution?

Answer 24

By changing the ratio of acid to salt or by choosing a different acid and specific salt

Question 25

How does an acidic buffer solution resist changes in pH when an acid is added?

Answer 25

The newly introduced H+ combine with the ethanoate ions to make enthanoic acid.
This moves the equilibrium position to the left.

Question 26

How does an acidic buffer solution resist changes in pH when an alkali is added?

Answer 26

1) removal by reacting with HA
This is more like to happen
pH unlikely to change

2) removal by reacting with H+
OH- combine with these to make water
However this moves equilibrium to the right in order to make up for lost H+

Question 27

In the acid dissociation constant, [H+] =

Answer 27

Ka x ([HA]/[A-])