Question

When a magnesium ribbon burns in air and the ash formed is dissolved in water:
A. The water solution if ash is basic in nature
B. This is a chemical change
C. Both A and B are correct
D. Both A and B are wrong

Answer 1

Magnesium oxide is a substance that is obtained on burning of magnesium. Further, we obtain another substance on mixing magnesium oxide and water. To solve this question, we need to know the nature of these substances and what type of changes occur during these processes.

Complete step by step answer:
First of all, let’s discuss magnesium. It is considered as the most chemically active element. It is labeled as the eighth most abundant element in the Earth’s crust. It has an atomic number 12 and symbol Mg. Now, let’s talk about magnesium ribbon. When this ribbon is burnt in air, it combines with oxygen to form white powder i.e. magnesium oxide and further releases heat and light. Magnesium gives up two electrons to oxygen atoms and form this powdery white product. The reaction is as shown:
$2Mg + {O_2} \to 2MgO$
Further, magnesium hydroxide is another substance formed by mixing magnesium oxide with water. Hence, this process is a chemical change and magnesium hydroxide is basic in nature.

Hence, option A and B both are correct.

Note: Basically, a chemical change happens when one chemical substance is transformed into one or more different substances. One such example is when iron becomes rust. Moreover, these changes occur through the process of chemical reactions and the resulting substances have different properties because their atoms and molecules are arranged differently.