Let us demystify this for you.

Baking soda and Baking Powder are both leaving agents. The product carbon
dioxide and make the cooked food  'rise' like cakes.

Baking soda

Baking Soda  is pure Sodium Bicarbonate. When it combines with some
acidic ingredient and moisture it results in a chemical reaction which produces
Carbon Dioxide gas bubbles  as soon as you mix it with the other
ingredients, therefore you need to cook your dish as soon as you add the baking
soda otherwise it will tend to go flat, like coke left open for long.

Baking Powder

Baking powder contains baking soda(sodium bicarbonate) plus some acidifying
agent  (cream of tartar), and a drying agent (usually starch).



Baking powder is available as single-acting baking powder and as double-acting
baking powder. Single-acting powders are activated by moisture, so you must bake
recipes which include this product immediately after mixing. Double-acting
powders react in two phases and can stand for a while before baking. With
double-acting powder, some gas is released at room temperature when the powder
is added to dough, but the majority of the gas is released after the temperature
of the dough increases in the oven.

How to determine when to use the Baking Soda or the Baking Powder in your
recipe?

When you use the Baking Soda you would need some acidic ingredient to create the
reaction ( eg. yoghurt, butter milk etc). otherwise it will result in a bitter
taste.

Baking Powder is a premix which already has a acidic medium , so the end
result will be a neutral effect in terms of the taste.

In cakes and biscuits you normally do not use any acidic ingredient,
therefore you need to use the Baking Powder so that it can cause the rising
action on its own.

Can I substitute Baking Powder in place of Baking Soda? -
YES

As already said the Baking Powder already has the Baking Soda in it, though
lesser quantity then pure baking soda. Therefore you can use baking powder in
place of baking soda but you would need more quantity of Baking Powder to
achieve the equivalent results.

 Can I substitute Baking Soda in place of Baking Powder? -
NO

Normally no - as already said you would need an acidic medium to cause the
reaction with the Baking Soda.  If you are making a cake and if you want to
add baking soda in place of the baking powder, it will not work well as it will
not have any acidic medium to react with. So the cake will not rise.


Baking Soda ( 1/2 teaspoon) disolved in water in the morning and evening said to be of help for Gout. Here is a link where some users has given testimonials how the Baking Soda has helped them. http://www.icuredmygout.org/

Though I tried it on myself and I did not get any gout relief, the day I had the baking soda the next day my gout was worse.