Which of the following is composed of the element, \(H , O\), Al, and Si?
A. Urea B. Silica C. Bauxite D. Clay
Correct Answer: D
Explanation
Clay is a mixture of quart, mica and other substances bound together by hydrated silicates of aluminium. The silicate has the formular \(Al _{2} Si _{2} O _{7} .2 H _{2} O\). Silica is silicon dioxide \(\left( SiO _{2}\right)\), urea has the formular and bauxite, a principal ore of aluminium has the formular \(Al _{2} O _{3} \cdot 2 H _{2} O\)
