The cake rises, causing it to be lighter and airier.
nope
Most cake recipes call for baking powder. It will give more lift than soda.
The cake will not rise properly.
Yes
Bicarbonate of soda and baking soda are the same thing. If you are referring to baking powder, please check the provided link which explains the difference between baking soda and baking powder, and what happens if you use them together.
No, there is no need to. The mix has baking powder already in it.
Self raising flour makes the cake rise, but if you don't have any you can use plain flour and baking powder which has the same effect. 225g plain flour and 4 teaspoons baking powder, will transform it into self raising flour.
Make one with each. The baking powder will perform better.
Yes, it's still effective. Refrigeration will not change the properties of baking soda.
Baking powder and baking soda are not directly interchangeable. If baking powder is used, one should reduce the amount of salt in the recipe, as well as reduce or eliminate any added acidic ingredient such as vinegar or lemon juice; replace buttermilk with regular milk.
It's not the milk alone that makes a cake rise. If the recipe includes milk it probably also contains either baking powder and/or baking soda. This combination of a base (Baking soda or Baking Powder) and an acid (milk) causes a slight chemical reaction which causes the cake to rise.
nothing really