Magnesium reacting in monoprotic strong acid

[shredder666]

If I have x moles of magnesium and y moles of a monoprotic strong acid (I'm talking about something like 0.03 moles or less of each reactant with the magnesium being the limiting reactant) the there's going to be a noticable pH change right?

Because I remember my teacher showing us the titration curve of a strong acid titrated with a strong base, there was that S-shape (or Z-shape) , where the first few drops of strong base didn't really change the pH at all and then there was that sudden change. Is that going to be the same case with strong acid "titrated" with magnesium?

I'm also wonder how fast, in terms of seconds (a rough estimate), would the reaction be for magnesium metal reacting with HCl, and how complete the reaction will be, is all of the magnesium going to react with the hydrogen gas and not participate in some reverse reaction?

 

[Borek]

Depending on the values of x and y there can be or can be not noticeable change in pH. However, you will not get fast change of pH as in titration, as you will not get pH above 7.

You won't get speed estimate, as it depends on many factors - the most important ones being metal surface and the way solution is mixed. I think it will be up to several minutes if you put a thin Mg ribbon in 1M HCl.

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[quicknote]

I would like to clarify that the reaction between magnesium and a monoprotic strong acid, such as hydrochloric acid, will indeed result in a noticeable change in pH. This is because the reaction between magnesium and a strong acid is highly exothermic, meaning it releases a large amount of energy. This energy is released in the form of heat, which can be detected as a change in temperature and pH.

Regarding your question about the titration curve, the shape of the curve will depend on the exact concentrations of the reactants and their respective volumes. However, in general, the curve will start off with a gradual increase in pH as the acid is neutralized by the base, and then there will be a sharp increase in pH once the acid is fully neutralized. This is due to the sudden increase in hydroxide ions from the base reacting with the remaining hydrogen ions from the acid.

In terms of reaction speed, it is difficult to estimate the exact time it would take for the reaction to occur without knowing the specific conditions and concentrations. However, in general, the reaction between magnesium and hydrochloric acid is quite fast and can occur within seconds. As for completeness, the reaction between magnesium and hydrochloric acid is highly favorable and will typically go to completion, meaning all of the magnesium will react with the acid to form magnesium chloride and hydrogen gas. There is typically no significant reverse reaction in this case.

Overall, the reaction between magnesium and a monoprotic strong acid is a well-studied and understood process in chemistry. It is important to carefully control the concentrations and conditions in order to accurately predict the outcome and observe the expected changes in pH.