6.1 Properties of Acids and Bases

Question 1

What is acid is HI?

Answer 1

Hydroiodic acid (monoprotic) STRONG

Question 2

What acid is HBr?

Answer 2

Hydrobromic Acid (monoprotic) STRONG

Question 3

What acid is HCl?

Answer 3

Hydrochloric Acid (monoprotic) STRONG

Question 4

What acid is H2SO4?

Answer 4

Sulphuric Acid (diprotic) STRONG

Question 5

What acid is HNO3?

Answer 5

Nitric Acid (monoprotic) STRONG

Question 6

What acid is H2SO3?

Answer 6

Sulphurous acid WEAK

Question 7

What acid is H3PO4?

Answer 7

Phosphoric Acid WEAK

Question 8

What acid is HNO2?

Answer 8

Nitrous Acid WEAK

Question 9

What acid is CH3COOH?

Answer 9

Acetic Acid (ethanoic acid) WEAK

Question 10

What acid is HF?

Answer 10

Hydrofluoric Acid WEAK

Question 11

What acid is H(Cit)3?
(C₆H₈O₇ or HOC(CH₂CO₂H)₂)

Answer 11

Citric Acid WEAK

Question 12

3 common properties of acids

Answer 12

sour, turns blue litmus red, reacts with reactive metals

Question 13

Acid + reactive metal →

Answer 13

hydrogen gas + salt

Question 14

Acid + carbonate →

Answer 14

CO2 + salt + water

Question 15

Acid + metal oxide →

Answer 15

salt + water

Question 16

Acid + metal hydroxide →

Answer 16

salt + water

Question 17

what is an acid

Answer 17

any solution that forms H+ ions in water

Question 18

What is an inorganic acid?

Answer 18

a compound containing hydrogen and non-metallic atoms or their groups

Question 19

what is an organic acid?

Answer 19

any compound with directly connected C&H

Question 20

organic vs inorganic base

Answer 20

organic if a base includes C,
inorganic (everything else) includes OH or O2- or metallic atoms

Question 21

nomenclature for monoatomic ion in acid

Answer 21

hydro-[X]-ic acid

Question 22

nomenclature for polyatomic ion in acid ending in -ate

Answer 22

-ic acid

Question 23

nomenclature for polyatomic ion in acid ending in -ite

Answer 23

-ous acid

Question 24

what is a base

Answer 24

any substance that forms OH- ions in water

Question 25

3 common properties of bases

Answer 25

soapy feel (aqueous), bitter, turns litmus paper blue

Question 26

neutralisation reaction

Answer 26

acid + base –> salt + water
usually EXOTHERMIC

Question 27

explain neutralisation of ant bites

Answer 27

has formic acid HCOOH, neutralised with baking soda NaHCO3

Question 28

explain neutralisation of indigestion

Answer 28

HCl neutralised with antacid tablets Mg(OH)2

Question 29

NOTE all enthalpy reactions will release…

Answer 29

heat loss into environment/equipment

Question 30

alkalis are…

Answer 30

soluble bases

Question 31

juices vs cleaners

Answer 31

acidic vs basic

Question 32

what is pH

Answer 32

“power of hydrogen” measuring acidity/alkalinity by concentration of hydrogen (or hydronium) ions on logarithmic scale from 0-14

Question 33

hydronium

Answer 33

H3O+ (water with added hydrogen)

Question 34

what are indicators

Answer 34

tools measuring pH using two different coloured chemical species

Question 35

indicator equilibrium

Answer 35

HIn + H2O ⇌ In- + H3O+

HIn molecule = protonated form of indicator (more acidic)
In- ion = unprotonated form of indicator (more basic)

HIn and In- are two different colours

Question 36

methyl orange range and colours

Answer 36

3.1 - 4.4, orange to yellow

Question 37

phenolphthalein range and colours

Answer 37

8.2 - 10, red to colourless

Question 38

bromothymol blue range and colours

Answer 38

6.0 - 7.6, blue to yellow

Question 39

4 natural indicators

Answer 39

anthocyanin, cochineal, litmus, hydrangeas

Question 40

concentration of H+ at 25C

Answer 40

[H3O+] = 1 x 10-7 mol L-1
then [H+] = 1 x 10-7

Question 41

Equilibrium constant for water self ionisation

Answer 41

Kw = [H3O-] x [H+] = x2
= 1 x 10-14 mol L-2 at 25oC

Question 42

2 logarithmic equations for pH

Answer 42

pH = -log10[H+]
[H+] = 10^ (-pH)

Question 43

3 acid/base conjugate pair equations

Answer 43

pH + pOH = 14

Ka x Kb = Kw = 1.0 x 10-14 at 25oC
Kw = [H3O+] x [OH-]

Question 44

(LCP) increase temperature → equilibrium moves to lower temperature by absorbing extra heat →

Answer 44

favours forward reaction → equilibrium shifts right → more hydroxide ions formed → Kw value increases

Question 45

2 equations involving pOH

Answer 45

pOH = -log[OH-]
[OH-] = 10^ -pOH

Question 46

acids sting/burn, while alkalines feel…

Answer 46

slippery

Question 47

strong acids ionise…

Answer 47

completely

Question 48

concentration vs strength

Answer 48

conc. = number of ions/molecules mol/L;
strength = degree/percentage of ionised molecules

Question 49

when are acids/bases electrolytes

Answer 49

soluble acids
aqueous bases

Question 50

oxides of the first 2 periodic groups are

Answer 50

basic, e.g. KOH, NaOH…

Question 51

4 steps making red cabbage indicator

Answer 51

1) chop cabbage into small pieces
2) boil until coloured
3) strain and cool at room temp
4) decant

Question 52

3 steps: how to test red cabbage

Answer 52

1) prepare test tubes of various pH
2) add indicator
3) record differentiations across pH

Question 53

weak acid neutralisation reactions use what arrow?

Answer 53

equilibrium arrow