What is baking soda used for?
Baking soda, or Sodium bicarbonate (NaHCO3), has the following applications:

* Leavening agent in baking. When it reacts with acidic components or when heat applied to it carbon dioxide is released which causes the expansion of the batter by creating gas babbles. 

* Mild disinfectant and a fungicide against some organisms.

* Neutralizer of acids or an ingredient in preparing weak base solutions when dissolved in water.

* Cleaning agent in removing oil, paint and corrosion mostly from metallic substrates.
Can I use it to clean a baking tray from an greasy crust?