What is meant by the term 'acid rain'. Give any two impacts of acid rain.

The term 'acid rain' refers to the various ways in which the acids formed in the atmosphere - condense and fall on the earth resulting in acid rain.

Impacts of acid rain :

1. Nutrient leaching — The hydrogen ions which are added to the soil when acid rain falls on the earth interact chemically with existing soil minerals.
   H₂SO₄ ⇌ 2H¹⁺ + SO₄^2-
   Minerals like potassium and calcium interact with the H¹⁺ ions and are displaced from the soil, thus the soil is deprived of nutrients.
2. Affects marine organisms — Toxic metals like mercury, lead, zinc present in the soil, get leached by acid rain thus toxicity enters rivers and streams and destroys aquatic plants and animals.