name the gas evolved when dilute hcl reacts with sodium hydrogen carbonate. how is it recognised?

NaHCO₃ + HCl ------> NaCl + CO₂+H₂O

so, carbon dioxide gas is released which can be identified by the following tests:

1)  A hissing sound on evolution of carbon dioxide with brisk effervescence (bubbling) in the test tube.
2. On passing the gas through freshly prepared lime water, it will turn milky because of formation of insoluble calcium carbonate.

Ca(OH)₂ + CO₂ -------> CaCO₃ + H₂O

3. If you keep a moist blue litmus paper over the test tube, it will turn red as carbon dioxide is acidic in nature.