Acid deposition (acid rain)

Question 1

Why is rain naturally slighly acidic? (pH 5.5)

Answer 1

Dissolved CO₂ in it forms weak carbonic acid

Question 2

Sources of acid deposition and the gases they produce?

Answer 2

1. Power plant: SO₂ & NO_x
2. Vehicle exhausts: SO₂ & NO_x
3. Volcanoes: SO₂
4. Factories

Question 3

Series of equations that form acid rain from sulfur

Answer 3

1. S + O₂ →SO₂
2. 2SO₂ + O₂ → 2SO₃
3. SO₃ + H₂O → H₂SO₄

Question 4

Series of equations that form acid rain from nitrogen

Answer 4

1. N₂ + O₂ → 2NO
2. 2NO + O₂ → 2NO₂
3. 2NO₂ + H₂O → HNO₃ + HNO₂

Question 5

4 negative consequences of acid deposition

Answer 5

• Increase solubility of Ca and Mg in soil;leaching
• Corrodes limestone buildings
• Makes Al more soluble; toxic to fish and when absorbed by plants
• Damages leaves of plants, so less photosynthesis and eventual death

Question 6

How to reduce the production of NO_x and SO₂

Answer 6

1. Wash coal to remove sulfur impurities
2. Scrubbers containing lime in coal plant chimneys;lime reacts with SO₂ in the flue gas
3. Stop using fossil fuels
4. Catalytic converters in cars

Question 7

How to correct acid depostion on soil

Answer 7

Add lime