In the given options, the example of a physical change is option B: mixing baking soda and vinegar.
Here's why:
1. Physical changes do not alter the chemical composition of substances involved, only their physical state or appearance.
2. When baking soda and vinegar are mixed, a fizzing reaction occurs due to the release of carbon dioxide gas. This reaction is a physical change because no new substances are formed; it's just a change in appearance and state.
3. Other options like souring milk, rusting metal, and mixing oil and vinegar involve chemical reactions where new substances are formed, indicating a chemical change rather than a physical one.
So, in this case, mixing baking soda and vinegar represents a physical change because it only affects the physical properties of the substances involved without creating new chemical compounds.
