Dear Student ,
We will use the formula :
Molarity (M) = no. of moles of solute / volume of solution in Litres
Na2S2O3.xH2O was dissolved in 1L of some solution. Now, 20 mL of this solution required 10mL of 0.01M iodine solution.
no. of moles = M * V ( from the above formula )
n ( iodine solution)= 0.01 * 10*10-3 = 10-4 moles
therefore , n ( solution) = 10-4 = Molarity of solution * volume of solution
10-4 = Msol * 20 * 10-3
Msol = 0.005
Now, 2.48 g of Na2S2O3.xH2O is dissolved in 1L this solution . So, it is behaving as solute . Again using the same formula we will find the value of x :
0.005 = moles of solute / 1 L
0.005 = given mass / molar mass
0.005 = 2.48 / {46+64+48+x (18)}
Now, solve this equation to get the value of x = ?
Chemistry Consultant
Askiitians