Normality

Asked by impuranik | 2nd Dec, 2010, 10:06: AM

Expert Answer:

Dear Student
 
Normality is defined as the number of gram equivalents of solute present per litre (dm3) of the solution at any given temperature. It is expressed as N.
The Normality of the solution can also be expressed in terms of mass and equivalent mass

In terms of weight, Normality of the substance can be expressed as:

Measurements in normality can change with the change in temperature because solutions expand or contract accordingly.

Example 1. 

36.5 grams of hydrochloric acid (HCl) is a 1 N (one normal) solution of HCl.

normal is one gram equivalent of a solute per liter of solution. Since hydrochloric acid is a strong acid that dissociates completely in water, a 1 N solution of HCl would also be 1 N for H+ or Cl-ions for acid-base reactions.

Example 2 Molecular wt of K2Cr2O7 is 294.148 gm. What is its normality in 1000 ml solution?

Valency = 6 (because of Cr -6)

EW = 294.148/6 = 49.025

N = 49.025/1000 ml = 0.049025.

We hope that clarifies your query.
Regards
Team
Topperlearning

Answered by  | 2nd Dec, 2010, 10:47: AM

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