Which statement correctly describes a physical change?
a. involves breaking and creating chemical bonds but not changing a phase
b. may involve a change in phase but does not involve a change in the molecular structure
c. may involve converting two or more substances into new substances
d. involves changes at the molecular level
d. involves energy transfer and change in color

Option (b) is the correct answer.

Explanation:

A change which brings no change in chemical composition of a substance is known as a physical change.

For example, melting of ice is a physical change as there occurs change in phase from solid state to liquid state of water. Whereas the structure of water remains the same.

Therefore, we can conclude that the statement which describes a physical change is that it may involve a change in phase but does not involve a change in the molecular structure.