Meta boric acid and tetra pyro acids are unstable in solution because they undergo hydrolysis reactions to form boric acid and pyroboric acid, respectively. These hydrolysis reactions are driven by the high reactivity of the B-O bonds in these compounds, which are susceptible to attack by water molecules.

In the case of meta boric acid, the hydrolysis reaction can be represented as follows:

H3BO3 + H2O → B(OH)4- + H+

This reaction results in the formation of boric acid (B(OH)3) and a hydrogen ion (H+). The tetra pyro acid undergoes a similar hydrolysis reaction to form pyroboric acid (H2B4O7) and hydrogen ions:

H2B4O7 + H2O → 2B(OH)4- + 2H+

These hydrolysis reactions are typically slow at room temperature, but they can be accelerated by the presence of acids or bases, which can catalyze the reactions. As a result, meta boric acid and tetra pyro acids are generally not used in applications where they will be exposed to water or other sources of moisture.