Baking powder is a mixture of ‘X’ and a mild edible acid such as ‘Y’. When it is heated, ‘Z’ is produced which makes bread and cake soft and spongy X, Y and Z respectively are

Baking powder is a mixture of baking soda (sodium hydrogen carbonate) and a mild edible acid such as tartaric acid. When baking powder is heated, ${\mathrm{CO}}_2$  gas is produced which causes cakes, bread and puff’s to rise, making them soft and spongy