In everyday chemistry, dry ice is the common name given to which substance in its solid state?

Introduction / Context:
Dry ice is widely used for cooling and special effects such as fog in stage performances, and it is often mentioned in science demonstrations. However, many people do not realize exactly what chemical substance dry ice is. This question tests your knowledge of the identity of dry ice and reinforces the connection between common names and chemical names in basic chemistry.

Given Data / Assumptions:

• The term used is dry ice.
• The question refers to the substance in its solid state.
• Options include solid and gaseous forms of carbon dioxide and other compounds such as baking soda and carbon monoxide.

Concept / Approach:
Dry ice is known for subliming directly from the solid to the gas without forming a liquid under normal atmospheric pressure. In classrooms and laboratories, it is used to demonstrate sublimation and to create dense white fog by cooling moist air. These behaviors match solid carbon dioxide, CO2, which is stored at very low temperature and pressure conditions to remain solid. The correct option must therefore link dry ice specifically with solid carbon dioxide, not other carbon compounds or gaseous carbon dioxide.

Step-by-Step Solution:
Step 1: Recall that dry ice is associated with the gas carbon dioxide, CO2. Step 2: Note that the question clearly mentions the solid state of the substance. Step 3: Recognize that dry ice is used to create fog and cooling effects by sublimation, which is a property of solid CO2 under normal pressure. Step 4: Compare the options and identify the one that states solid carbon dioxide. Step 5: Select solid carbon dioxide as the correct description of dry ice.

Verification / Alternative check:
To verify, think about how dry ice is handled. It is stored in insulated containers and produces carbon dioxide gas as it warms, which can displace air and cause suffocation hazards in closed spaces. This is consistent with solid CO2 subliming into gaseous CO2. Safety datasheets and chemistry references also list dry ice as the solid form of carbon dioxide. No other common chemical fits this description or usage pattern so precisely.

Why Other Options Are Wrong:
Option B, baking soda, refers to sodium bicarbonate, NaHCO3, which is a white powder used in cooking and cleaning, not a low temperature solid that sublimes. Option C, gaseous carbon dioxide, describes CO2 in the gas phase rather than in the solid form that is called dry ice. Option D, carbon monoxide, CO, is a toxic gas and is not referred to as dry ice. These alternatives do not match the physical properties and common uses of dry ice.

Common Pitfalls:
A common misunderstanding is to assume that any cold solid associated with carbon must be some form of ice similar to water ice. Some students also mix up carbon dioxide and carbon monoxide because their formulas look similar. Remember that dry ice specifically refers to solid carbon dioxide, which behaves differently from water ice and from other carbon compounds. Keeping the connection between dry ice and solid CO2 clear will help you avoid confusion in exams and practical discussions.

Final Answer:
Dry ice is the common name for solid carbon dioxide.