Option 1: It is used in soda-acid fire extinguisher. This statement is correct. Baking soda, also known as sodium bicarbonate, is commonly used in soda-acid fire extinguishers. When baking soda reacts with acid, it releases carbon dioxide, which helps to smother the fire.

Option 2: It is added for faster cooking. This statement is incorrect. Baking soda is sometimes used in cooking to help batter rise and create a lighter texture in baked goods. However, it is not added for faster cooking. Baking soda helps in the leavening process by releasing carbon dioxide gas when it reacts with an acid, but it does not speed up the cooking time.

Option 3: It is a corrosive base. This statement is correct. Baking soda is an alkaline substance, which means it is a base. However, it is not considered a corrosive base. Baking soda is generally safe to handle and use for cooking purposes.

Option 4: It neutralizes excess acid in the stomach. This statement is correct. Baking soda can be used as an antacid to neutralize excess stomach acid. It is commonly used to provide temporary relief from heartburn and indigestion.

In conclusion, option 3