5. Gain and Loss of Electrons   Previous PageNext Page
       Carbon and Carbonic Acid

Carbon monoxide, like the isoelectronic molecule, is barely soluble in water. Carbon dioxide dissolves easily in water to form carbonic acid:

This is a weak acid with a sharp taste, familiar from carbonated soft drinks. The bubbles in a carbonated drink are incompletely dissolved gas.

When dissolves in water, the carbon atom attracts a lone pair from the oxygen of a water molecule and forms carbonic acid, which has the structure shown on the next page. The carbon atom is double-bonded to one oxygen atom, and single-bonded to each of two OH groups.

Since carbon is moderately electronegative and the C-O bond in C-O-H is stronger than the O-H bond, the carbonic acid molecule dissociates in water by losing protons, and therefore is an acid. Dissociation takes place in two steps:


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