Why are silica stationary phase height limited to operating in the pH range $\mathbf{2}\mathbf{-}\mathbf{8}$?why does the silica in figure$\mathbf{25}\mathbf{-}\mathbf{8}$have improved stability at low pH?

Silica is also used in the grinding and polishing of glass and stone, as well as in the production of glass, ceramics, silicon carbide, ferrosilicon, and silicone.

Because silica dissolves above $pH=8$And the siloxane bond hydrolyzes below $pH=2$,

silica stationary phases are generally limited to operating in the pH range

$2-8$.Figure $25-8$shows that silica has improved stability at low pH due to the presence of bulky isobutyl groups.

As a result of the interference between the approach of${\mathrm{H}}^{+}$

And the siloxane bond, acid-catalyzed hydrolysis occurs is to avoid.

Hence,

Because silica dissolves above $pH=8$And the siloxane bond hydrolyzes below $pH=2$, silica stationary phases are generally limited to operating in the pH range

2-8 . Figure 25-8 shows that silica has improved stability at low pH due to the presence of bulky isobutyl groups. As a result of the interference between the approach of $H^{+}$.And the siloxane bond, acid-catalyzed hydrolysis occurs is to avoid.