Acid Deposition

Question 1

Is rain naturally alkali or acid?

Answer 1

acid because of presence of dissolved carbon dioxide - forms weak acid carbonic acid

Question 2

What are the equations of rain water?

Answer 2

Question 3

acid rain

Answer 3

• solutions with a pH below 5.6
• contain additional acids

Question 4

what are the main contributors to acid rain?

Answer 4

• oxides of sulfur and nitrogen
• primary pollutants

Question 5

is acid rain a primary or secondary pollutant?

Answer 5

secondary pollutant

Question 6

acid deposition

Answer 6

all processes by which acidic components as precipitates or gases leave the atmosphere

Question 7

what are the two types of acid deposition?

Answer 7

• wet acid deposition
• dry acid deposition

Question 8

wet acid deposition

Answer 8

rain, snow, fog fall to ground as aqueous precipitates

Question 9

dry acid deposition

Answer 9

gases fall to ground as dust and smoke and dissolve in water to form acids

Question 10

sulfur oxide equations

Answer 10

either 1,2 or 1,2,3,4

Question 11

nitrogen oxide equations

Answer 11

• either 1,3 or 2
• THEN
• either 4 or 5

Question 12

impact on limestone for sulfur dioxide, sulfuric acid and nitric acid equations

Answer 12

erodes buildings and statues

Question 13

impact on metals for sulfur dioxide, sulfuric acid and nitric acid

Answer 13

• increases rate of rusting
• removes oxide layer on metal surfaces like Al

Question 14

impact of acid rain on plant life

Answer 14

• slows growth and injures plants through leaching
• dry deposition blocks pores for gas exchange

Question 15

leaching

Answer 15

acid rain causes important minerals (Mg²⁺, Ca²⁺, K⁺) held in soil to become soluble and wash away before they can be absorbed by plants

Question 16

acid deposition impact on water

Answer 16

• lakes become too acid to support life
• eutrophication occurs

Question 17

eutrophication

Answer 17

• over-fertilization of bodies of water caused by nitrates in acid rain
• results in algal blooms leading to oxygen depletion

Question 18

acid deposition impact on health

Answer 18

• sulfate and nitrate particles irritate respiratory tract
• increase risk of asthma, bronchitis and emphysema
• irritate eyes

Question 19

pre-combustion methods of reducing SO₂​ emissions

Answer 19

• processes that reduce or remove sulfur present in coal or oil before combustion
• crush coal and wash with water: high density sulfide sinks to bottom and separates from clean coal
• hydrodesulfurisation: catalytic process that removes sulfur from refined petroleum products by reacting it with hydrogen to form hydrogen sulfide, used to manufacture sulfuric acid

Question 20

post-combustion methods of reducing SO₂ emissions

Answer 20

flue-gas desulfurization: wet slurry reacts with SO₂ to form neutral calcium sulfate - used to make plasterboard

Question 21

reduction of NO_x​ emissions

Answer 21

• catalytic converters in vehicles: hot gases mixed with air pass over a platinum catalyst which converts toxic emissions into harmless products (picture = equation)
• lower temperature combustion: recirculating exhaust gases back into engine lowers temperature to reduce emissions
• lower demand for fossil fuels

Question 22

method to restore acid rain damaged ecosystems

Answer 22

lime neutralises acid