How to solve this question???

Lets try to solve this type of question: (example of the calculation)

5 ml of Oxalic acid (H₂C₂O₄) stock solution is pipet to prepared 250mL oxalic acid in the volumetric flask. 25 mL of the H₂C₂O₄ solution is used to titrate with 0.2M NaOH solution. Volume of NaOH used in the titration is as follows:

Burette Reading (mL)	Gross	I	II	III
Final	41.70	25.30	30.70	27.80
Initial	16.00	00.00	6.00	2.50
Volume titrant (NaOH) used

   

•              Calculate the molarity of dilute H₂C₂O₄
•               Calculate the molarity of stock solution H₂C₂O₄

Solution:
Calculate molarity of dilute solution:
* we can calculate molarity of dilute solution from titration process between acid and base
* Write and balance the equation between acid and base

H2C2O4  + 2 NaOH ------->  Na2C2O4   +  2H2O

*Calculate average volume of NaOH used in the experiment (exclude gross reading)
* use formula to calculate Molarity

MaVa  =  1
MbVb     2
(Ma) (25)   =  1
(0.2 (25.10)    2
Ma (dilute)  = 0.1004M

Calculate Molarity of Stock Solution:
 M1V1 = M2V2

(M1) (5) = (0.1004) (250)
 M1(stock) = 5.02M