Which of the compounds is composed of Al, Si, O and H?

A. Epson salt
B. Limestone
C. Clay
D. Urea

Correct Answer:

Option C – Clay

Explanation

Between the five main minerals found in clay, kaolinite is the most common. Kaolinite holds the chemical composition Al2Si2O5(OH)4 and is an aluminum silicate material with a low “shrink-swell” capacity. It is a soft, white mineral but is often colored orange or red by iron oxide found in the soil.