Which gas is formed when you mix sugar and coke?

When you mix sugar and Coke, the primary gas that is formed is carbon dioxide (CO2). This gas is already present in Coke due to carbonation, but adding sugar can cause the release of more CO2 from the solution, leading to fizzing or bubbling. The reaction is not a chemical one but rather a physical reaction where the sugar interacts with the carbonated beverage, potentially increasing the effervescence.