Kinetics of metals reacting with acids

[james111]

hey. I am doing an investigation into reactions of acids with Mg. Firstly, iv investigated how order with respect to the acid varies for different acids
i found that the orders for each of the acids are:

Hydrochloric acid: 2
Sulphuric acid: 1
Phosphoric acid: 1.8

in an article, it said that: the effect of added sodium and magnesium chlorides indicated that high concentrations of added salt slow down the reaction considerably. There is other evidence that small concentrations of added sodium chloride increase the rate of reaction, and it is well known that sodium chloride solution alone is highly corrosive to magnesium, far more so than solutions of nitrates or sulphates.

how would i find out the order of the reaction with respect to Cl- ions?? someone said they did it and they got a negative order, which would make comply with what was said above.

for the orders experiment i just used a relatively simple pracitcal setup- using a range of acid concs and noting the time it took for a certain mass of Mg to disappear. Plotting log rate (=log 1/time) vs log conc acid, i determined the order by the gradient of the graph. Unfortunately, i can't think of a similar way to determine how the order of Cl- ions or SO42- ions using a similar method. thanks for any help

(apparently, i was told that by applying thermodynamics to this problem, i would be able to find out whether the reaction is SN1 or SN2...but i can't figure that one out either. any suggestions please?)

i no that iv written quite a bit and would appreciate any help.

thanks.

 

[james111]

anyone??

 

[Blueshift5]

I find your investigation into the kinetics of metals reacting with acids very interesting. It is important to understand the factors that affect the rate of a reaction, as it can have significant implications in various industries such as pharmaceuticals and chemical manufacturing.

Based on your findings, it seems that the order of the reaction with respect to the acid varies depending on the type of acid used. This could be due to the different properties of each acid, such as its strength and concentration. It would be helpful to further investigate the reasons behind these variations and how they affect the reaction.

Regarding your question about finding the order of the reaction with respect to Cl- ions, it is possible that the negative order obtained by the other person could be due to errors in their experimental setup or calculations. It would be best to repeat the experiment and compare your results with theirs to see if there are any discrepancies.

In terms of applying thermodynamics to determine whether the reaction is SN1 or SN2, it would require a deeper understanding of these mechanisms and their thermodynamic properties. I suggest consulting with a chemistry expert or doing further research on the topic to gain a better understanding.

Overall, your investigation is a good starting point, and I encourage you to continue exploring and experimenting to gain a better understanding of the kinetics of metals reacting with acids. Good luck with your research!