No, baking soda is not polar. It is, however, Ionic.
Baking powder is Sodium Bicarbonate a polar compound that is particularly amenable to water (a polar solvent). So Baking powder will dissolve faster than a non-polar powder like Talcum powder. Also baking power is very finely ground and will present a large surface area to the water which hastens dissolving. Salt in comparison although a strongly polar compound is course ground and will take longer to dissolve.
Benzene is a non polar solvent. Gelatin powder is a polar solute. So gelatin powder in insoluble in benzene.
Because "like dissolves like" eg. polar substances dissolve polar substances. Mothball powder, margarine, and kerosene are all non-polar. Water however is polar, so the mothball powder and margarine cannot dissolve in it.
Baking Powder
Baking powder in a recipe helps your item rise when baking.
baking powerder is baking powder is not the same!
baking powder
Self rising flour is flour with baking powder and salt added to it. It is also finer, therefore it is good for baking because if you use regular flour you have to add the baking powder to it.
Baking soda does not rise as well as baking powder
No, baking powder does not absorb odors when used in baking.
baking powder is neutral
Baking powder is an acid