Given below are two statements: Statement I: Acid rain dissolves and washes…
2023
Given below are two statements:
Statement I: Acid rain dissolves and washes away nutrients in the soil.
Statement II: Acid rain does not dissolve naturally occurring toxic substances.
In the light of the above statements, choose the most appropriate answer from the options given below:
Answer: C. Statement I is correct but Statement II is incorrect — CONCEPTAcid deposition lowers soil pH. Extra hydrogen ions displace nutrient cations from soil-exchange sites. The lower pH can also increase the solubility…
- A.
Both Statement I and Statement II are correct
- B.
Both Statement I and Statement II are incorrect
- C.
Statement I is correct but Statement II is incorrect
- D.
Statement I is incorrect but Statement II is correct
Attempted by 1 students.
Show answer & explanation
Correct answer: C
CONCEPT
Acid deposition lowers soil pH. Extra hydrogen ions displace nutrient cations from soil-exchange sites.
The lower pH can also increase the solubility and mobility of naturally occurring metals.
APPLICATION
For Statement I, when calcium, magnesium and potassium ions are displaced, water can leach them below the root zone. Thus nutrient loss follows from the ion-exchange effect of acidification.
For Statement II, the same acidity can dissolve or mobilize naturally occurring toxic metals, especially aluminium, into soil water. Therefore the claim that acid rain does not dissolve such substances conflicts with this mechanism.
CONTRAST
“Both statements are correct” accepts nutrient leaching but excludes toxic-metal dissolution.
“Both statements are incorrect” rejects nutrient leaching even though acidification displaces nutrient cations.
“Statement I is correct but Statement II is incorrect” includes both nutrient leaching and the possible mobilization of toxic metals.
“Statement I is incorrect but Statement II is correct” excludes both effects of lower soil pH.
RESULT
Therefore, Statement I is correct and Statement II is incorrect.