The short video from American Chemical Society was so interesting. It shows the chemistry of bread baking.
Yeasts are actually living microorganisms. Once in contact with warm water, the yeast added feeds on the sugars in flour and produces carbon dioxide. The release of carbon dioxide makes bread rise.
Baking soda works more quickly than yeast. Baking soda consists of sodium bicarbonate, calcium acid phosphate & corn starch. Bread dough rises faster as chemical reaction occurs and produces carbon dioxide.