titration and various standard solution

Titration:

Titration is the process of calculating the concentration of unknown solution by reacting with another solution of known concentration is known as titration.

 During the process, one of the solution pipetted out in a conical flask whose volume is known. Another solution is kept in burettte. Solution from burette is allowed to fall on conical flask till the reaction completes. The concentration of one of the solution will be given and using V1N1=V2N2 , concentration of the unknown solution is measured.

Titrant: 
The solution of known concentration during titration is titrant.
Titrand:
  The solution of known concentratioin and whose concentration is to be determined by titration process is called titrand.

Equivalent point:
   During titration the reaction completes when no. of gm eq. of titrant becomes equal to no. of gm. equivalent of titrand. The point where the no. of equivalent of titrant and no. of gm. equivalent of titrand and no. of gm equivalent of titrand becomes equal is called equivalent point. It is theoritical point.

End point:
The practical point, during titration which indicates the completion of reaction by color change of indicator is called end point.

Titration error:
 The difference between value of end point and equivalent point is called titration error.

Normal solution:
   The solution which is prepared by dissolving 1 gm. equivalent of solute (Equivalent weight of solute) in 1 litre solution is called Normal solution. It is represented by N.
   Therefore, the solution prepared by dissolving 53 gm Na2co3 in 1 lit solution is the example of Normal solution.

Decinormal solution:
   The solution which is prepared by dissolving 1/10th part the equivalent weight of solute in 1 litre solution is called Decinormal solution. It is represented by N/10.
      Therefore, the solution prepared by dissolving 5.3 gm Na2Co3 in 1 litre solution is the example of decinormal solution.

Seminormal solution:
    The solution which is prepared by dissolving 1/2th part of the equivalent weight of solute in 1 litre solution is called seminormal solution. It is denoted by N/2 . Therefore, the solution prepared by dissolving 26.5 gm Na2co3 in 1 litre solution is the example of semi-normal solution.

Centrinormal solution:
     The solution which is prepared by dissolving 1/100th part the equivalent weight of solute in 1 litre solution  is called centrinormal solution. It is represented by N/100.
   Therefore, the solution is prepared by dissolving 0.53 gm of Na2co3 in 1 litre solution is the example of centrinormal solution.
How will you prepare decinormal solution of Na2Co3?
----> Let us suppose we have to prepare 500ml solution. First of all,we have to calculate the weight of Na2co3 that is to be taken by using relation.

w=NEV/1000
=2.65 gm.
Hence, 2.65gm Na2co3 is transferred into volumetric flask of respective capacity. Water is added with continuous stierring . As all Na2co3 get dissolve, the volume is maintainted upto the mark. Since Na2co3 is primary standard substances. So, prepared solution will be exactly decinormal.

Primary standard solution:
---> There are certain substance whose standard solution can be prepared directly by dissolving calculated amount of solute in define volume of solution are called primary standard substance and the solution prepared from this substances is called primary standard solution. eg oxalic, Na2co3.

Condition for the substance to be primary standard solution are -
(i) The substance should not be hygroscopic and diliquescence.
(ii) It's composition shouldn't be change during storage either in solution form or in pure form for certain time period.
(iii) It should be easily available in laboratory.
(iv) It should be readily soluble in water.
(v) It should have high equivalent weight to minimize weighting error.

Secondary standard solution:
    There are certain substances whose standard solution can't be prepared directly by the weighting method. This substance are called primary standard substance and the solution prepared from the substances will not be of known concentration. Concentration of so prepared solution is calculated by tit-rating with another standard solution.