Which one among the following chemicals is used as washing soda ?

Washing soda is the common name for sodium carbonate (Na2CO3) [1]. It is an inorganic salt used extensively in the glass, soap, and paper industries, and serves as a cleaning agent for domestic purposes [1]. Chemically, it is distinct from baking soda, which is sodium bicarbonate (NaHCO3). Sodium carbonate is particularly effective in laundry and water treatment because it can remove permanent hardness from water [1]. While sodium bicarbonate is a mild alkaline used in baking and antacids, sodium carbonate is a stronger alkaline with a higher pH, making it more suitable for heavy-duty cleaning and industrial processes. It is often produced via the Solvay process and can exist in an anhydrous form known as soda ash or a hydrated form known as washing soda.

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 2: Acids, Bases and Salts > Uses of washing soda > p. 32