Question

Arrange the following oxides in the decreasing order of their relative abundance in the Earth's crust:
A. \(Al_2O_3\),
B. \(Fe_2O_3+FeO\),
C. \(CaO\),
D. \(SiO_2\). Choose the correct answer from the options given below:

• A. D, A, B, C
• B. D, A, C, B
• C. A, D, C, B
• D. A, C, B, D

Hint:

Silica \((SiO_2)\) is the most abundant oxide in the Earth's crust.

Answer 1

The Correct Option is A

Concept:
The Earth's crust is dominated by silicate minerals, so silica is the most abundant oxide.

Step 1: Identify the most abundant oxide.
Silica \((SiO_2)\) is the most abundant oxide in the Earth's crust. \[ D \text{ comes first} \]

Step 2: Identify the second most abundant oxide.
Alumina \((Al_2O_3)\) is next after silica. \[ A \text{ comes second} \]

Step 3: Compare iron oxides and calcium oxide.
Total iron oxides are generally more abundant than calcium oxide. \[ B>C \]

Step 4: Final decreasing order.
Therefore, the decreasing order is: \[ SiO_2>Al_2O_3>(Fe_2O_3+FeO)>CaO \] Using letters: \[ D>A>B>C \] \[ \therefore \text{Correct Answer is (A)} \]