Why does buffer capacity increase as a solution becomes very acidic (pH≈1) or very basic (pH≈13)?

A metal ion in aqueous solution, also known as an aqua ion, is a cation with the chemical formula ${\left[M_n\right]}^{\mathbf{z}\mathbf{+}}$that is dissolved in water. Various experimental approaches have revealed that the solvation number, n, for ${\mathbf{Li}}^{\mathbf{+}}$and ${\mathbf{Be}}^{\mathbf{2}\mathbf{+}}$is 4 and for elements in periods 3 and 4 of the periodic table is 6.

(a)

Given,

Mass of water in air (balance reading) is 5.3974 g.

The density of air is 0.0012g/mL.

Density of balance weight is 8.0G/mL.

It is known that density of water at $15°\mathrm{C}$is 0.9991026 g/mL.

The given mass of water, density of water at$15°\mathrm{C}$, density of air, and density of balance weight are plugged in above equation to give true mass of water.

The true mass of water at$15°C$ is 5.4031g.

(b)

Given,

Mass of water in air (balance reading) is 5.3974 g.

The density of air is 0.0012g/ mL.

Density of balance weight is 8.0g/mL.

It is known that density of water at $25°C$is 0.9970479g/mL=5.4031g

The given mass of water, density of water at $15°C$, density of air, and density of balance weight are plugged in above equation to give true mass of water.

The true mass of water at $25°C$is 5.4031g.