chemical

• when its heated, bicarbonate of soda breaks down to produce carbon dioxide bubbles that expand to make the mixture rise
• bicarbonate of soda has an unpleasant alkaline taste so it needs to be used with a strong flavour to mask it. this is why its used in things like gingerbread and chocolate cake
• baking powder is a mixture of bicarbonate of soda and cream of tartar. a neutralisation reaction takes place when baking powder is heated which gets rid of the soapy taste
• self - raising flours contain a mixture of plain flour and baking powder