When E is a metal, it will form a basic oxide which dissolves in water to form an alkaline solution.
When the element E is a metal, it typically forms a basic oxide when it undergoes combustion in oxygen. Metal oxides are characterized by their ability to react with water to produce hydroxides, leading to the formation of alkaline solutions. In this context, when the product of the combustion of element E (metal) is soluble in water, the resulting aqueous solution will exhibit alkaline properties.
The term "alkaline" indicates that the solution will turn neutral litmus paper blue, confirming its basic nature. This behavior is a common characteristic of metals, and the presence of hydroxide ions in the aqueous solution is responsible for the alkaline properties.