Question

Which type of weathering involves the outer layer of rock peeling off due to expanding as it is heated and contracting as it cools?
a)Hydration
b)Insolation weathering
c)Oxidation
d)Carbonation

Answer 1

Hint:Weathering and erosion are two processes that are responsible for our changing landforms. Weathering refers to breaking down of rocks and minerals while erosion means the process by which materials are worn away and transported from one location to another.

Complete Answer:Water, plants, animals, acid, changes in temperature are all agents of weathering.
Let us look at the options given to us

Option (A ) Hydration is a kind of chemical weathering where chemical bonds between minerals alter as they react with water.

Option (C ) oxidation is a type of chemical weathering where minerals react with oxygen to form oxides. For example rusting is a type of oxidation.

Option (D ) carbonation is a type of chemical weathering where carbonic acid forms due to reaction of water and carbon dioxide ,and this carbonic acid disintegrates the minerals. This type of weathering is seen in the formation of caves.

Option (B) insolation weathering is also known as thermal stress weathering .Due to heat of the sun the minerals expand and then contract as sun sets and temperature cools down. This is a type of physical weathering where repeated heating and cooling of rock over daily cycles breaks apart the grains of the rock.
Therefore, option B is correct.

Note:One needs to understand the difference between erosion and weathering. Weathering refers to disintegration of material while erosion refers to displacement of material. Weathering is of two types-physical and chemical.Chemical weathering includes solution, carbonation, hydration, oxidation and reduction on the rocks to decompose, dissolve or reduce them to a fine clastic state. Physical weathering refers to disintegration of solid due to some applied force.