Reaction rates...?

Question

How can i measure the reaction rate between HCl and NaOH?
Its just an acid base reaction, i dont see what product could be measured as such

And help/ideas would be much appreciate

Answer 1

There are several simple ways of measuring a reaction rate. For example, if a gas was being given off during a reaction, you could take some measurements and work out the volume being given off per second at any particular time during the reaction.

A rate of 2 cm3 s-1 is obviously twice as fast as one of 1 cm3 s-1.



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Note: Read cm3 s-1 as "cubic centimetres per second".

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However, for this more formal and mathematical look at rates of reaction, the rate is usually measured by looking at how fast the concentration of one of the reactants is falling at any one time.

For example, suppose you had a reaction between two substances A and B. Assume that at least one of them is in a form where it is sensible to measure its concentration - for example, in solution or as a gas.



For this reaction you could measure the rate of the reaction by finding out how fast the concentration of, say, A was falling per second.

You might, for example, find that at the beginning of the reaction, its concentration was falling at a rate of 0.0040 mol dm-3 s-1.



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Note: Read mol dm-3 s-1 as "moles per cubic decimetre (or litre) per second".

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This means that every second the concentration of A was falling by 0.0040 moles per cubic decimetre. This rate will decrease during the reaction as A gets used up.

Summary

For the purposes of rate equations and orders of reaction, the rate of a reaction is measured in terms of how fast the concentration of one of the reactants is falling. Its units are mol dm-3 s-1.

hope this helps

Answer 2

Its a unique scenario as the only reaction product is identical to the solvent in which the reaction occurs. Since the reaction takes place in water, attempting to measure the amount of water produced by the reaction would be pointless.

Any attempt to use chemical indicators would run into the problem of the reaction rate of H+/OH- ions reacting with the acid/base species present in the indicator.

The only way I can see is to measure the concentration of H+ or OH- electronically. Unfortunately "glass electrode" pH detectors have speed problems themselves as the solution has to cross a semi-permeable membrane, which also takes time.

There may be a spectroscopic method of measuring the concentration of H+ or OH- ions. Whether it would be fast enough to measure this reaction is another question.

Also, you would have to develop a method of mixing the reactants to get a time=0 point to start from. By the time the solution is "properly" mixed the reaction will most likely be over.

[edit] The reaction is exothermic, so you could attempt to measure the change in temperature against time. I wouldn't think that technique would be fast enough either, but its an idea. I would say that spectroscopy would probably be the best method.

Answer 3

You could use a data logger to measure pH change during a titration (the acid and alkali must be mixed instantaneously)although the probes will have a time delay (an alternative may be conductivity measurements as the ions will conduct and this will have minimal time delay, you would have to set up a calibration graph showing the conductance of known concentrations of ionic solutions to make correlations). The reaction is between the H+ ion and the OH- So You can calculate the amount of acid present at any stage. This is fairly easy to set up as HCl dissociates 100% in water and at neutralisation there will be vertually no H+ or OH- present.

Hope this helps.

Answer 4

First of all an acid and base reaction gives you salty plus water. Hcl + NaoH = NaCl+ H2O. Before the reachtion the acid will measure ph scale below seven and the base will measure above seven. After the reaction the the ph scale will measure 7neutral.

Answer 5

As you know, in that reaction, you are just forming water. My impression is that the reaction between H+ and OH- is an exceedingly fast one, so I can't think of a way that you could easily measure its rate.

I'd be interested to know if you find a way to do that one...

Now, there are some acid-base reactions that you can fairly easily measure the rate of. I know there are some pH indicators that change color when they react with H+ or OH-, and the reactions are slow enough to easily measure. Those reactions are fairly standard kinetics labs. Let me know if you want more information about those...

Answer 6

reaction fee exhibits the speed that reactants bypass to products and reaction time exhibits the time it takes. reaction time and reaction fee are inversely proportional, and at the same time as the speed will enhance, the time decreases.

Answer 7

Yes.