Answer:
The correct answer is CO2
Step-by-step explanation:
Carbon dioxide (chemical formula CO 2) has 60% greater density than dry air and is a colorless gas. It is the most soft and malleable crystal from the option given in the question. It exists as a trace gas on earth in nature.
Carbon dioxide is soluble in water and is mostly found in springs and groundwater. One carbon dioxide molecule consists of one carbon atom and two oxygen atoms. Usually when it is in normal concentrations, it is odorless whereas it has a strong acidic smell under high concentrations.