ACIDS & BASES

Question 1

arrhenius theory

Answer 1

in aq,

acid = gives H+
base = gives OH-

not all acids are soluble in water

Question 2

bbl theory

Answer 2

acid = proton donor

base = proton acceptor

HCl + H2O ⇌ H3O+ + Cl- [H+ donated]
NH3 + H2O ⇌ NH4+ + OH- [H+ accepted]

limited to protonic solvents

can’t explain acid-base reactions that dont involve proton transfer

Question 3

lewis theory

Answer 3

acid = electron pair acceptor

base = electron pair donor

Question 4

properties de acids y bases

Answer 4

pH < 7
sour

pH > 7
soapy/slippery
bitter

Question 5

strong acid vs weak acid

Answer 5

complete dissociation vs partial dissociation

HCl → H+ + Cl-
CH3COOH → H+ + CH3COO-

if in water, H+ will react with water to form hydronium ion H3O+

Question 6

litmus paper

Answer 6

acid = blue litmus → red
base = red litmus → blue

Question 7

bromthymol blue

Answer 7

blue base
yellow acid
green neutral

Question 8

methyl orange

Answer 8

acid = red
base = neutral = yellow

Question 9

test for hydrogen

Answer 9

lighted splint burns with a pop

Question 10

test for oxygen

Answer 10

glowing splint relights

Question 11

test for ammonia

Answer 11

damp red turns blue

Question 12

test for chlorine

Answer 12

damp blue turns red then bleaches white

Question 13

test for co2

Answer 13

in CaOH turns milky white due to presence of insoluble white CaCO3 precipitate

caoh = lime water

Question 14

use of NH4NO3

Answer 14

fertilizers

Question 15

use of KNO3

Answer 15

gunpowder

Question 16

use of MgSO4

Answer 16

medicine

Question 17

use of CaCO3

Answer 17

marble, marine animal shell, statues, limestone

Question 18

Na2CO3?

Answer 18

washing soda

Question 19

NaHCO3

Answer 19

baking soda

Question 20

what is oxide

Answer 20

compounds made from one or more atoms of oxygen combined with one other element

Question 21

give example of amphoteric oxide

Answer 21

Al2O3 forms complex aluminate salts with bases and simple salts with acids

Question 22

types of oxides

Answer 22

1. metal oxides (basic)
2. non-metal oxides (acidic)
3. amphoteric (these show both acidic and basic propeties)
4. neutral (these show neither acidic nor basic properties)

Question 23

how to form a soluble salt

Answer 23

1. acid-base titration
2. acid + excess reactive metal (not very reactive metal because reaction is very violent)
   * use excess so that all acid reacts and the salt does not have any acid in it.
3. acid + excess metal carbonate/bicarbonate

Question 24

acid base titration

Answer 24

put acid in beaker, use phenolphthalein as indicator first time and stop when it becomes slightly pink which shows the solution is neutral then repeat without indicator

Question 25

how to form insoluble salt

Answer 25

(1) direct combination (just put them together and heat) * Fe+S=FeS (2) precipitation method * NaI+AgNO3 = AgI + NaNO3 ## Footnote SNAP are soluble (sodium, nitrate, ammonium, potassium) so the precipitate has to be AgI

Question 26

acid rain

Answer 26

* volcanic eruptions, burning of fossil fuels release sulphur and nitrogen oxides. * in car engine enough energy for N and O to fuse and form NO. * when released through exhaust in atmosphere, if thunder strikes perfectly, the NO released bonds with another O to form NO2. * when rain happens SO2 and NO2 reacts with water to form nitric and sulfurous, sulfuric acid ## Footnote normal rain = slightly acidic because of presence of co2

Question 27

catalytic converter

Answer 27

* attached to exhaust, reduces NO to N2, which is not a pollutant * however causes increased exhaust noise and sometimes engine performance issues.

Question 28

hydrodesulfurization

Answer 28

(of crude oil) sulphur content is removed so that upon fractional distillation, it's components also don't have sulphur hence reducing carbon emissions immensly

Question 29

pros of hydrodesulfurization

Answer 29

* lower sulfur levels minimize corrosive effects on pipeline * lowers maintenance costs for vehicles

Question 30

cons of hydrodesulfurization

Answer 30

* high pressure and temp required * high operational costs * produces hydrogen sulfide (H₂S) which is a toxic and corrosive gas ## Footnote processes that extract hydrogen from gases like methane release a lot of carbon emissions

Question 31

acid+metal

Answer 31

salt+hydrogen gas | single displacement reaction, na+hcl→nacl+h2

Question 32

acid+base

Answer 32

salt+water | metal oxides and hydroxides are basic in nature ## Footnote double displacement reaction, koh+h2so4→k2so4+h2o

Question 33

metal carbonates/bicarbonates+acid

Answer 33

salt+co2+h2o | carbonates are salts of carbonic acid and are weak bases ## Footnote caco3+hcl→cacl2+co2+h2o