The correct answer is option 3: Sodium carbonate. Sodium carbonate is commonly known as washing soda. It is a chemical compound that has the formula Na2CO3.
Option 1: Calcium carbonate is not used as washing soda. It is a different compound that is commonly found in rocks and minerals, such as limestone and marble. It is used in various industries, including the manufacturing of cement and as a dietary supplement.
Option 2: Calcium bicarbonate is not used as washing soda either. It is a compound that forms when calcium carbonate reacts with carbonic acid. It is commonly found in natural spring waters and is responsible for the "hardness" of water.
Option 4: Sodium bicarbonate is different from sodium carbonate and is commonly known as baking soda. It is used in baking, as a household cleaner, and as an antacid.
In summary, sodium carbonate, or option 3, is the correct chemical compound used as washing soda.