Question

What is the difference between carbonate and bicarbonate?

Answer 1

Hint: Carbonate and bicarbonates both are inorganic compounds that have different physical and chemical properties. Though they have similar physical appearances, they greatly differ in their chemical properties.

Complete Step By Step Answer:
Carbonate ions consist of one carbon atom and three oxygen atoms. It is a divalent anion and has a charge of -2. The geometry is trigonal planar and the molecular weight is 60 g/mol. The carbonate structure shows a resonance stabilisation. Hence the hybrid structure of carbonate is the most stable. The oxygen atoms have partial negative charge.

Bicarbonate is a monovalent anion having one carbon 3 oxygen and one hydrogen atom. On deprotonation it forms carbonic acid. The geometry is trigonal planar and has a molecular weight of 61 g/mol. This ion shows a resonance structure between two oxygen atoms, which are not connected to hydrogen. Bicarbonate is alkaline in nature and the conjugate acid of carbonate ion. On reacting with acids it releases carbon dioxide.

The key difference between carbonate and bicarbonate is the charge on the compounds; carbonate has -2 charge and bicarbonate has -2 charge. The molecular weights are also different because of the presence of Hydrogen atoms on bicarbonate which is 61 g/mol whereas carbonate is 60 g/mol.
Another difference is that in highly alkaline conditions carbonate ions will be more whereas in weakly alkaline conditions bicarbonate ions will be more. The carbonate is not soluble in water at room temperature and atmospheric pressure, whereas bicarbonate is easily soluble in water at room temperature.

Note:
Sodium carbonate and bicarbonates are known as baking soda and baking powder respectively. Baking soda is used in cookies and cakes for the levelling of the substance whereas baking powder is used for complete levelling and for longer storage of the product.