While possible, you will have to different cakes. In texture and height.
no you do not you need self raising flour though
Baking powder and yeast help in the rising of a bread or cake. If it is expired, then it won't be as "active" and therefore decreasing it's ability to rise which makes for a poor bread or cake.
You should bake it for another 5-10 minutes
The amount of baking powder required depends entirely on what you intend to bake. Different types of cookies, muffins and other baked goods require different proportions of baking powder to flour.
Yes, you can use self rising flour to bake a cake. Just leave out any baking soda, baking powder or salt called for in the recipe, as these are already included in self rising flour.
the purpose of baking powder in a cake is to make it rise and not make it flat and if you put too much of baking powder your cake might burst in the oven/microwave what ever you use
In other to make honey cake it need the volume from baking powder to raise and also baking powder help the cake to form the the honey comb mixture.
Most cake recipes call for baking powder. It will give more lift than soda.
nope
The cake rises, causing it to be lighter and airier.
Baking powder is a leavening agent, which is what causes the cake to rise. Too little baking powder will cause the cake to be tough and compact, and won't rise as expected.
Baking powder is a leavening agent and will result how airy your final product will be. However, cake, bread and muffins all have different levels of airiness. You'd need to specify what you're trying to bake to give us a good idea how much baking powder you need.