Question

Which statement is true about the two changes (X and Y) described below?

X: A green banana turns yellow and ripens emitting the characteristic banana smell.

Y: A layer of rust forms on an iron nail.



a
X is a physical change due to a change of state, but Y is a chemical change because new molecules are formed.
b
Both are chemical changes because new substances are formed.
c
X is a chemical change due to a change of state, but Y is a physical change because new molecules are formed.
d
Both are physical changes because only the physical state of the substances change.

Answer 1

b

Both are chemical changes. Ripening of a banana involves biochemical reactions that produce new compounds (color and aroma change), and rusting is oxidation of iron to form new compounds (iron oxides).