how does titration relate to concentration of solutions?

Question

Say after I did the experiment for titration and I got several results, what are the next steps I should do to check out their concentration? If I don't know what the solutions are and their molecular formua, is it possible to still continue doing the calculations for titration.

Do you know of any steps to calculate concentration involving titration results.

Also, what are possible sources of error?

Answer 1

titration works on the principle the product of the normality and volume of one solution is equal to the product of the normality and volume of another solution which neutralizes it.so we take a known volume of a solution whose concentration we want to find out and add to it just the exact quantity of another solution whose concentration is known to neutralize the first solution and fine out the concentration of the unknown solution using the formula N1V1=N2V2
you must know the equivalent weights of the solutions involved
normality of a solution is the no of gram equivalents in a liter of the solution
possible sources of error will be
1.error due to parallax
2.error in noting down the end point of the titration

Answer 2

Physandchemteach you should be ashamed! That formula is correct only under certain conditions.

The general formula is like mentioned in the first anwer:

N1V1=N2V2

which simply means that titration is completed when you have added the same amount of chemical equivalents of titrant with that of the solution you are measuring. It could be acid/base or redox reaction. N=aM where a is the number of H+/OH- per acid/base molecules or number of electrons in case of redox.

So you have a1M1V1=a2M2V2 as a general formula for calculating the concentration in mole/lt.

You need to know what your solutions are, otherwise it is impossible to determine a1 and a2.

Errors could be due to different things.

1.As mentioned in the first answer if you didn't observe the level of the titrant from the right angle you would make a mistake in the volume.
2.If you added titrant too fast you could have overestimated the actual volume needed for the titration.
3. Preparation of the titrant. You should use proper glassware and be very thorough to ensure the accuracy of the titrants concentration.
4.Bad choice of an indicator. E.g. Weak acids have equivalence point at pH=2*pKa so you need an indicator in that region.
5. Some titrants need to be standardized by measuring with another standard solution since their concentration might vary (I think for example in the case of iodine)
6. Error in determining the end of the titration due to insufficient stirring (strange but I have seen people doing it)

Answer 3

Have your read through your lab instructions carefully? I can't believe you did a titration with two unknown solutions. Go back and read everything. In a titration you are comparing the amount of a standard solution needed to neutralize an amount of unknown concentration solution. Once you determine how much of the standard solution and how much of the unknown solution are used the calculations are simple:

(Molarity)(Volume) for the standard = (Molarity)(Volume) for the unknown.

You know the molarity of the standard (given in lab)
You know the amount of standard used in the neutralization (reading from buret)
You know the amount of unknown used (how much you put in the beaker to start)
All you do is put them into the equation to calculate the molarity of the unknown solution.