Which alkali used in saponification gives hard soap and which one gives soft soap?

Saponification is the process of making soap. The type of alkali used in this process determines whether the soap will be hard or soft.

1. Hard Soap: Sodium hydroxide (NaOH), also known as lye or caustic soda, is used in the saponification process to produce hard soap. When fats or oils are treated with sodium hydroxide, the resulting soap is hard and is more resistant to dissolving in water.

2. Soft Soap: Potassium hydroxide (KOH), also known as caustic potash, is used to produce soft soap. When fats or oils are treated with potassium hydroxide, the resulting soap is softer and more easily dissolves in water.

So, in summary, sodium hydroxide is used to produce hard soap, and potassium hydroxide is used to produce soft soap.