Question

Two changes are given below.
(i) A piece of magnesium gives off bright flames when
burnt.
(ii) A piece of iron glows red hot when heated strongly.
Which of these is a chemical change ?
(A) i only
(B) ii only
(C) both i and ii (D) neither i nor ii​

Answer 1

Answer:

(i) is correct...

If correct mark as brainliest answer....

Answer 2

Option(A) is correct.

1. Physical change is a change in which the substance changes form but keeps its same chemical composition (reversible).
2. A chemical change (chemical reaction) is a change of materials into other, new materials with different properties, and one or new substances are formed. In the first reaction.
3. Magnesium burns with oxygen to form a compound magnesium oxide, thus forming new compound.
4. Hence, this is chemical change.
5. In the second option, iron rod becomes red hot.
6. Though the composition of iron remains same.
7. Thus, it is not counted as chemical change, hence it is physical change.