Question

When a magnesium ribbon is burnt in the air, the ash formed is

• A. Black
• B. White
• C. Yellow
• D. Pink

Answer 1

The correct option is B

White

Explanation for the correct option:

(B) White

• The burning of Magnesium ($\mathrm{Mg}$) in air produces Magnesium oxide ($\mathrm{MgO}$) which is white in colour.
• Air consists of Oxygen, therefore, it involves the reaction of Magnesium with Oxygen.
• $$\begin{gathered} 2\mathrm{Mg}\left(s\right)+{\mathrm{O}}_2\left(g\right)\to 2\mathrm{MgO}\left(s\right) \\ \mathrm{Magnesium}\mathrm{Oxygen}\mathrm{Magnesium}\mathrm{Oxide} \end{gathered}$$

Explanation for the incorrect options:

(A) Black

• The product of the reaction is Magnesium oxide ($\mathrm{MgO}$) which is white in colour.

(C) Yellow

• The product of the reaction is Magnesium oxide ($\mathrm{MgO}$) which is white in colour.

(D) Pink

• The product of the reaction is Magnesium oxide ($\mathrm{MgO}$) which is white in colour.

Hence, option (B) is correct. The ash formed is white.