K⁺ ion is a constituent of sodium pump.

MgCO₃ $$\buildrel \Delta \over \longrightarrow $$ MgO + CO₂

84 g of MgCO₃ $$ \equiv $$ 40 g of MgO

$$ \therefore $$ 20 g of MgCO₃ = $${{40} \over {84}} \times 20$$ = 9.52 g of MgO

But Actual yield = 8 g of MgO

$$ \therefore $$ % purity = $${8 \over {9.52}} \times 100$$ = 84%

Carbonates becomes more thermally stable down the group, Also, the alkali metal carbonate are more stable than alkaline earth metal carbonates. Therefore MgCO₃ will leave CO₂ easily.

MgCO₃ $$\buildrel \Delta \over \longrightarrow $$ MgO + CO₂

In Castner-Kellner cell, sodium amalgam is formed at mercury cathode.