Question

Which chemical weathering process involves action of carbonic acid such as rocks like limestone?
a)Hydration
b)Carbonation
c)Solution
d)Oxidation

Answer 1

Hint:Weathering is a process by which rock and matter get decomposed or disintegrated on being acted by agents like water, acid, animals, pressure , temperature etc. Weathering can further be divided into chemical weathering and physical weathering.

Complete Answer:Chemical weathering is the process by which chemical bonds of a mineral are changed due to processes like hydration, oxidation, solution etc.
Lets us look at the options given to us-
Option (A ) Hydration is a type of chemical weathering by which chemical bonds of minerals are altered as the mineral reacts with water.For example reaction of anhydrite with underground leads to gypsum.

Option (C ) solution weathering is a type of chemical weathering where certain minerals get weathered as they dissolve into acidic solution

Option (D ) oxidation is a type of chemical weathering where minerals react with oxygen to form oxides. Rusting is an example of oxidation.

Option (B) Carbonation is the correct as carbonation refers to weathering caused by carbonic acid. Dissolved carbon dioxide in rainwater or moist air forms carbonic acid which then reacts with minerals susceptible to carbonation like limestone. Limestone , which is mostly calcium carbonate, reacts with carbonic acid to form caves , sinkholes and Karst topography.

Therefore, the correct option is option (B).

Note:Unlike chemical weathering, physical weathering causes disintegration and decomposition of rocks and minerals because of application of force. Examples of physical weathering include freeze and thaw weathering , isolation heating, exfoliation, unloading etc.