Recycle the old ammonia bottle. Label the new container clearly. Heat the new container to seal the lid. Store the new container in the refrigerator.
I gave my students this multiple choice question: A scientist lost the cap to an ammonia bottle, so she moved the ammonia into a clean container with a lid. What else should she do to be safe?

Only one answer is correct among these 4 choices:
- Recycle the old ammonia bottle.
- Label the new container clearly.
- Heat the new container to seal the lid.
- Store the new container in the refrigerator.

Could you tell me which one is correct?

Label the new container clearly.