Question

A number of elements available in earth’s crust but most abundant elements are:
(A). $Al$ and ${\text{Fe}}$
(B). $Al$ and $Cu$
(C). $Fe$ and $Cu$
(D). $Cu$ and $Ag$

Answer 1

Crust is the outermost solid shell of a rocky planet, dwarf planet or natural satellite. It can be easily distinguished from its underlying mantle by its chemical makeup. It is said to be made up of several elements.

Complete step by step answer:
The earth is composed of four distinct layers named as the inner core, the outer core, the mantle and the crust as ranging from the deepest to the shallowest part of the earth.
The crust of the earth ranges $5$ to $70{\text{ km}}$ below the surface of earth. This layer contributes only up to $1\%$ of the entire volume of the earth. The thinner parts of the oceanic crust underlie at a depth of $5$ to $10{\text{ km}}$ whereas the continental crust is the thicker crust.
The upper section of the mantle and the crust together constitutes the lithosphere.
The crust is made up to solid rocks and minerals. It is the most rigid of all the layers of earth and almost all the geological activities that affect the earth take place on the lithosphere.
The most abundant elements in the earth’s crust are oxygen, silicon, aluminum iron etc.
Aluminium is one of the most abundant elements in earth’s crust. It doesn’t exist as an element but it is found as a compound.
These include oxides and hydroxides of Aluminium, Sulphates and Potassium Aluminium sulphates. A number of processes are involved which can be used to extract aluminium from its compounds. This element is ideal to be found on earth’s crust as it is light in weight. Its composition is about $80,700{\text{ ppm}}$.
Iron also exists in the earth’s crust and has a composition of approx. $50,500{\text{ ppm}}$ . Iron ore exists in the earth’s crust in the form of its oxides such as hematite and magnetite and later, iron can be extracted from its ore. Blast furnaces are used for this purpose.
In all the given options, Aluminium $\left( {Al} \right)$ and iron $\left( {Fe} \right)$ are the most abundant elements on the earth’s crust.

So, the correct answer is Option A .

Note:
The earth’s crust is important as it supports human and plant life. The crust of earth is made up of igneous rocks and modified by volcanism, erosion and sedimentation. On the earth’s crust, dry and hot rocks from the deep earth react with water and oxygen present at the surface to make new kinds of minerals and rocks.