Question

how to make baking powder

Answer 1

To make baking powder, combine half a teaspoon of cream of tartar and quarter of a teaspoon of bicarbonate of soda. This provides the equivalent of one teaspoon of baking powder. Tomake self-raising flour add one teaspoon (or equivalent homemade) to 110g of plain flour

Answer 2

Baking powder is a raising agent that is commonly used in cake-making. It is made from an alkali, bicarbonate of soda, and an acid, cream of tartar, plus a filler like cornflour or rice flour which absorbs moisture. I think these ingredients can make baking powder.