The salts of strong acid and weak base give acidic solutions . Magnesium chloride is slightly acidic because it is formed by the reaction of a relatively weak base. Thus MgCl2 is slightly acidic in nature.

Why is NaCl more ionic than MgCl2?

As a group one element, sodium ionizes more easily that magnesium (a group two element). So sodium ionizes more readily that magnesium. Since the anion is the same in both cases (chloride), this could mean that NaCl is more ionic that MgCl2.

The covalent character is determined using Fajan’s rule. In the given compounds, the anion is the same and the cations are different. Therefore, MgCl2 is more covalent than NaCl.

Is magnesium chloride a strong acid?

As suggested by the existence of some hydrates, anhydrous MgCl2 is a Lewis acid, although a weak one. In the Dow process, magnesium chloride is regenerated from magnesium hydroxide using hydrochloric acid: Mg(OH)2(s) + 2 HCl(aq) → MgCl2(aq) + 2 H2O(l)

Both MgCl2 & MgSO4 are considered as acidic salts with the first coming from HCl & Mg(OH)2 “a weak base that is called Milk of Magnesia and is used as stomach antacid” & the second comes from H2SO4 & Mg(OH)2. When a salt is acidic then its pH will be lower than 7.