Question

Magnesium burns with a dazzling white flame to form magnesium oxide a powdery mass. The color of magnesium oxide is:
(A) milky white
(B) grey
(C) silvery
(D) yellow

Answer 1

Hint: Magnesium, a metal, is an extremely active chemical element. We know that Magnesium Oxide is the resultant formation when magnesium metal burns while reacting with the air, mainly oxygen. A chemical reaction occurs here, resulting in the formation of a new substance.

Complete answer:
Magnesium, as a metal, burns very quickly in air. Even so, in order to initiate the burning process or the reaction, the magnesium metal requires an external energy source. The fire or flame contributes heat, allowing the atoms present in the metal magnesium to surpass their activation energy. The activation energy is the minimal amount of energy needed for a chemical reaction to occur.
A compound is formed by the chemical reaction of air (oxygen) and metal magnesium. When it burns, it produces a compound that is a white powder of magnesium oxide. Magnesium Oxide is formed as the magnesium metal burns and encounters the air that is oxygen.
The following chemical equation can demonstrate the burning of magnesium metal in air:
$ \Rightarrow 2Mg + {O_2} \to 2MgO + energy\;(heat)$
To produce magnesium oxide the powdery substance, magnesium loses two electrons to the atoms of oxygen. This is a kind of exothermic reaction since heat is released in the formation of magnesium oxide. This reaction is also classified as a combustion reaction as magnesium produces heat and light when it encounters oxygen.
So we know that the powder of magnesium oxide that is produced after the burning of magnesium in air is white. Hence it is evident that the options: (B) grey, (C) silvery and (D) yellow colors are all wrong answers. So only option (A) contains the right answer, that is the color white or milky white.
Therefore the correct answer is clearly option (A) milky white.

Note:
Magnesium is an essential mineral that performs functions in the human body like: blood pressure regulation, assisting in muscle and nerve control, and immune system maintenance. Another application of the element is Magnesium's presence in flashbulbs. As the element magnesium burns, it emits a blinding light that is bright, which allows photographers to take images even in pitch black areas.