Question

Why can the Co2 concentration more than 0.05 percent become damaging for plant photosynthesis?

Answer 1

The formation of `H_2CO_3`

Explanation:

`CO_2` exists in water in an equilibrium with the equation:

`H_2O + CO_2 rightleftharpoons H_2CO_3`

The equilibrium for this equation is far to the left side (with water and carbon dioxide). When a lot of `CO_2` is present the equilibrium point moves to the right, causing more `H_2CO_3` form than usually. As `H_2CO_3` is an acid, damage to the proteins from the photosystems may occur.