MC test: Acid deposition

Multiple choice test on 8.5 Acid deposition

Use the following 'quiz' to test your knowledge and understanding of this sub-topic. You will need access to a periodic table (Section 6 of the IB data booklet).

If you get an answer wrong, read through the explanation carefully to learn from your mistakes.

Which is not a possible cause of acid deposition?

They are all acidic gases but normal rainwater already contains dissoved carbon dioxide.

 

Which reaction taking place inside an internal combustion engine appreciably leads to the formation of acid deposition?

At the high temperatures inside the internal combustion engine nitrogen and oxygen combine. The nitrogen monoxide emitted is then oxidized in the atmosphere to nitrogen dioxide which is one of the gases responsible for acid deposition. Some sulfur dioxide is produced (particularly in diesel engines) if the sulfur has not been removed from the fuel beforehand but only a tiny amount of this (<1%) is converted into sulfur trioxide inside the engine.

 

Which industrial processes can contribute significantly to acid deposition if prevention methods are not used?

I. coal-fired power stations

II. smelting of sulfide ores

III. oil-fired power stations

All fossil fuels contain sulfur. If it is not removed before combustion or, if the SO2 formed after combustion is not removed, it releases SO2 into the atmosphere, as does the smelting of sulfide ores.

 

Which process caused initially by nitrogen monoxide emissions from jet or automobile engines is not involved in contributing to acid deposition?

NO must first be oxidized to NO2 before acid deposition can occur. NO2 then either reacts directly with water to form a mixture of nitric and nitrous acids or is oxidized by oxygen in the rainwater directly to nitric acid.

 

Which effects are directly linked to acid deposition?

I. leaching of metal ions (such as Al3+) from the soil

II. global warming

III. increase in human respiratory illnesses

Global warming is caused by an increase in greenhouse  gases, most of which (e.g. CO2 and CH4) are not a cause of acid deposition.

 

Which is the correct ionic equation to describe the reaction that occurs when acid rain erodes marble statues?

As it is a statue, the carbonate ion must be in the solid state.

 

Why is rain with a pH of 6 not considered to be acid rain?

Acid rain is defined as precipitation (rain, snow, dew or fog) having a pH below 5.6, although in practice it is usually below 5. Oxygen does dissolve in rain but this does not affect its pH.

 

Almost all aquatic animal life will die in a lake when the pH falls below 4. What is the hydrogen ion concentration in lake water with a pH of 4?

pH = −log10[H+(aq)]. When pH = 4, [H+(aq)] = 1 x 10−4 mol dm−3.

 

How can the pH of a lake affected by acid deposition be raised?

Slaked lime is moderately soluble in water and the hydroxide ions will neutralize the hydrogen ions.

 

One method used in industry of removing sulfur dioxide formed when fossil fuels combust is to pass the flue gases though a slurry of lime (a mixture containing calcium hydroxide and/or calcium carbonate) - a process known as 'wet scrubbing'.

When sulfur dioxide reacts with the lime mixture what product is formed?

 

Essentially the reactions occurring are SO2(g) + CaCO3(s) → CaSO3(s) + CO2(g) and SO2(g) + Ca(OH)2(s) → CaSO3 + H2O(l).

 

Total Score:
All materials on this website are for the exclusive use of teachers and students at subscribing schools for the period of their subscription. Any unauthorised copying or posting of materials on other websites is an infringement of our copyright and could result in your account being blocked and legal action being taken against you.