2.48 g of hydrated sodium thiosulphate (Na_2S_2O_3 .xH_2O) was dissolved per litre of the solution. 25 mL of this solution required 12.5 mL of M /100 iodine solution . Determine the value of x.

2.48 g of hydrated sodium thiosulphate (Na_2S_2O_3 .xH_2O) was dissolv

1.	2.48 g of hydrated sodium thiosulphate (Na_2S_2O_3 .xH_2O) was dissolved per litre of the solution. 25 mL of this solution required 12.5 mL of M /100 iodine solution . Determine the value of x.
Answer» SOLUTION :The balanced chemical equation is : `2Na_2S_2O_3+I_2 rarr Na_2S_4O_6+2NaI` Let the MORALITY of `Na_2S_2O_3.xH_2O` be `M_1` Applying morality equation `((M_1V_1)/n_1)_(Na_2S_2O_3)=((M_2V_2)/n_2)_(I_2)` `(M_1xx25)/2-=1/100xx(12.5)/1` `M_1=(12.5xx2)/(100xx25)=0.01M` Molecular WT. of `Na_2S_2O_3.xH_2O` `=2xx23+2xx32+3xx16+xxx18` Amount of `Na_2S_2O_3.xH_2O=0.01xx(158+18x)g` But actural amount = 2.48 g `:.0.01(158+18x)=2.48` `(158+18x)=(2.48)/(0.01)=248` `18x=248-158=90` `:. x = 90 / 18 =5`.