Question

Baking soda is used in a small amount for making bread and cake. It helps to make these soft and spongy. An aqueous solution of baking soda turns red litmus blue. It is also used in soda-acid fire extinguishers.

Is the pH value of baking soda solution lower than or higher than 7?

Answer 1

• Baking soda is a salt of a strong base and weak acid.
• It is basic in nature, so its pH value will be greater than 7.
• Its actual pH value is 9.
• An aqueous solution of baking soda turns red litmus blue.
• Reaction for preparation of baking soda in the laboratory.

$$\begin{gathered} \mathrm{NaCl}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)+{\mathrm{CO}}_2\left(\mathrm{g}\right)+{\mathrm{NH}}_3\left(\mathrm{g}\right)\to {\mathrm{NH}}_4\mathrm{Cl}\left(\mathrm{aq}\right)+{\mathrm{NaHCO}}_3\left(\mathrm{aq}\right) \\ \mathrm{sodium}\mathrm{chloride}\mathrm{water}\mathrm{carbon}\mathrm{dioxide}\mathrm{ammonia}\mathrm{ammonium}\mathrm{chloride}\mathrm{baking}\mathrm{soda} \end{gathered}$$

Hence, baking soda is basic in nature its pH is higher than 7.