What is molarity

What is molarity?

It is the most broadly utilized unit and is indicated by M. Molarity is characterized as the quantity of moles of the solute in 1 liter of the arrangement.Thus,

Molarity (M)=No. of moles of solute  

 Volume of solution in litre

Example,

1) 5 moles of solute present in 500ml of solution,what is molarity?

Answer- Molarity (M)= 5 moles

                                            0.5 ltr

                                       = 5 × 10

                                               5

                                       = 10M

(Explained, 500 ml solutions means in litre is 0.5 ltr.)

Calculation of Molarity

For example,
1) 80 gm of NaoH present in 400 ml solution, What is Molarity?
Answer - moles of NaoH = 80 gm     

                                                40 moles
                                             = 2 moles
                       Molarity (M) = 2 moles
                                                  0.4 litre
                                               = 2×10
                                                    4
                                                = 5 M
(Explained, first we find moles of solute formula is,  moles of solute = weight of solute               )
                                     Molecular mass of solute)

Calculation for molarity

For mixing solutions, 

1) 500 ml of 1M sugar solution mix with 1 litre of 2M sugar solution?

Answer- Molarity= Total solute moles           

                                   Total volume of solution

First we find,[1] number of moles of solute

500 ml of 1M sugar solution,(A)=B× C

                                                          = 1×0.5 =0.5

 500 ml of 2M sugar solution,(A)=B×C

                                                          = 2×1= 2

 Molarity= Total solute moles           

                    Total volume of solution

                =(2+0.5) moles

                    1.5 litre

                  = 2.5

                      1.5   

                 = 1.67 M
(A= number of moles of solute, B = Molarity
 C = volume of solution in litre)

General expression to find molarity when similar solutions are mixed=
General expression=
M1,V1,L.                  M1V1+M2V2+M3V3+---------- 
M3,V2 L Resultant V1+V2+V3+---------
M3,B3 L molarity