Chloride Salts Lab Report

Abstract: This Extended Experimental Investigation assessed the effects of the chloride salts; Lithium Chloride, Sodium Chloride and Potassium Chloride on levels of dissolved oxygen in samples of distilled water. The three salts and a control solution of pure distilled water were titrated thrice, each using the Winkler method, to determine the quantity of dissolved oxygen within the samples. It was expected that the saline solutions would have decreased dissolved oxygen content and that the larger the salt’s cation, the more oxygen would remain in the solution. The results portrayed that an increase in salinity, does decrease the levels of dissolved oxygen in water, however the results displayed that the larger the dissolved cation, the less dissolved

(Lenntech, 2016). Diffusion being the process in which oxygen dissolves in water from kinetic movement, i.e. wave movement etc. (Hyperphysics, 2016). This means all water types contain some quantity of dissolved oxygen naturally when exposed to air sources. The dissolved oxygen in the samples used in this experiment would only have entered the water via atmospheric diffusion. As water molecules are highly polar, possessing partial positive and negative charges, they seek any molecules able to form intermolecular bonds and neutralize these partial charges via the formation of a hydration shell. This is the process of dissolution. Oxygen gas, not being polar, can only form a temporary bond with the polar water molecules called dipole-induced dipole. Water molecules hydrate oxygen molecules in water due to the polar oxygen molecules partial positive charges, pulling O2’s electron cloud closer to water forming a temporary and weak bond named above. This allows water molecules to form a hydration shell around O2 molecules, thus dissolving