Question

The percentage of abundance of three elements X, Y and Z in the earth’s crust are about 27.7, 8.3 and 46.0 by mass respectively. X, Y and Z are

• A. O, Si, Al
• B. Al, Si, O
• C. Si, Al, O
• D. Al, O, Si

Hint:

Oxygen is the most abundant element in Earth's crust.
Follow crustal abundance trend: O>Si>Al.

Answer 1

The Correct Option is A

According to geological data of earth’s crust composition: \begin{itemize} \item Oxygen is the most abundant element (~46%) \item Silicon comes next (~27.7%) \item Aluminium follows (~8.3%) \end{itemize} Therefore, based on the given mass percentages, the correct order of elements is: \[ Z = \text{Oxygen}, \quad X = \text{Silicon}, \quad Y = \text{Aluminium} \] So X, Y, Z = O, Si, Al.