Why is baking soda and vinegar have carbon dioxide?

The question is poorly Worded. A more precise question would be, "Why does a mixture of baking soda and vinegar release carbon dioxide?"

The reaction of baking soda and water is an acid-base reaction. The active ingredient of baking soda is sodium bicarbonate (NaHCO3), a base. The active ingredient of vinegar is acetic acid (H3COOH), an acid. The reaction of the two in water produces hydrocarbonic acid (H2CO3) plus sodium cations (Na+) and chloride anions (Cl-). The hydrocarbonic acid rapidly disproportionates into carbon dioxide (CO2) plus water (H2O).