Friday, May 6, 2016

Salt Dissolving And Metal Extraction

\(H_2O\), because of its partial charge, go between the bonded elements and weakens the ionic bond.  The salt lattice breaks up with some agitations, without explicitly removing the electrons.


\(NaCl\rightarrow Na+Cl\)

both not charged and will undergo further reactions with \(H_2O\).  \(H_2O^{-}\) and \(Na^{+}\) are not formed.  This is an separate issue from the unpaired orbit being filled with \(H\).

When \(Na\) acquires a \(H\),

\(Na+H_2O\rightarrow NaH+OH\)  --- (1)

where \(OH\) is not charged but its Oxygen \(O\) has an unpaired orbit.

Note: \(\bbox[red]{2Na+2H_2O\rightarrow 2NaOH+H_2 (\uparrow)}\)

I know. 

When \(Cl\) acquires a hydrogen from \(H_2O\),

\(Cl+H_2O\rightarrow ClH+OH\) --- (2)

Is \(HCL\equiv ClH\)?  Yes, the bond in \(HCl\) is covalent in nature.

Ionic salt dissolving in water is due to water polar nature that allows it to go between the elements in the ionic bond.  Water donating a Hydrogen to an unpaired orbit is a separate issue from dissolving.  It is possible that other polar liquids dissolve an ionic salt without filling any unpaired orbits.  In this case, the salt break up into its constituent elements without further chemical reactions.

Equations (1) and (2) have implications in the extraction of elements from salt mineral ore, when polar solvents other than \(H_2O\) are considered.  In order that the polar solvent penetrates into the salt lattice it may be necessary to apply high pressure.  For example, water from seawater is first displaced using a polar solvent, then pressure is applied to precipitate the elements of the ionic salt.  The polar solvent is designed such that it does not donate a hydrogen to the extracted elements, as water does in equation (1) and (2).  This way the extracted elements do not undergo further chemical reactions and remain pure.  The elements either separate naturally (as gas and solid) or be separated using a centrifuge.

Metals can be extracted from seawater cheaply, provided the suitable polar solvent that does not donate an hydrogen to the extracted metals can be created.

No need for electrolysis; but still when electrolysis is needed, without charged ions such as \(Na^{+}\), what did happen at the electrodes?