Class 12th "Solution" Chapter no. 02

Molarity : It is a solution which is the number of moles of the solute present in per liter of solution. 

(प्रति लीटर विलयन में घुलित विलेय पदार्थ के मोलों की संख्या को विलयन की मोलरता कहते हैं)। 

यह किसी निश्चित ताप पर ही हो सकता है। 

•  It is denoted by 'M'.

Formula :

  •    M = (number of moles of solute/volume of solution in liter) 

                        Or

                   M = n/v

Unit : mol/liter or mol/L

     

Formality : It is used to solve the concentration of ionic compounds solutions. Denoted by 'F'.

We could use gram formula mass for ionic compounds. Because they have no discrete molecules e.g. molecular mass word is not valid for that kind of compounds. 

"किसी निश्चित ताप पर प्रति लीटर विलयन में घुलित आयनिक पदार्थ के ग्राम सूत्र द्रव्यमान की संख्या विलयन की उस ताप पर फॉर्मलता कहलाती है।"

(Gram formula mass number of ionic compound soluble in a perticular temperature per liter solution is called formality.) 

Formula :  

•    [ Formality of solution = Gram formula mass number of solute/volume of solution in liter ]

                              

Molality : Number of moles of solute dissolved in 1000g(1kg) of solvent is called the molality of solution. 

(विलायक के 1000g में घुलित विलेय के मोलो की संख्या को विलयन की मोललता कहते हैं।) 

It is denoted by 'm'.

Formula :  

 

•   [ Molality = number of moles of solute/mass of solvent in kg.]

Unit :  mol/kg

•  Molality of solutions doesn't depends on temperature. 

Normality : It will denoted by 'N' 

किसी निश्चित ताप पर विलयन के 1 लीटर में घुलित विलेय के ग्राम तुल्यांकों की संख्या को उस ताप पर विलयन की नॉर्मलता कहते हैं। 

( Normality is defined as the number of equivalents per liter of solution.) 

Formula : 

[ Normality = Gram equivalents of solute/volume of solution in liter ]

[ Equivalent weight = Molar mass/number of moles ]

Unit :  gram equivalent per liter 

             or  g eq/L.

•  Gram equivalents of solute = mass of solute in gram/equivalent mass of solute. 

         

Practice Questions :

Q. 1.  What is differencw between Molarity and Normality. 

Q. 2.  What is the difference between Molality and Molarity. 

Q. 3.  Solution made by 0.63g of Oxylic acid missed with 100 cm^3 of water. Calculate the normality of solution. 

Q. 4.  What is the basicity. 

Q. 5.  Molality of solution 1.6 m in water of ethanol. Calculate the amount of ethanol in 500g solution. 

  

                       Thank You  !