15)An aqueous solution is 20.0% by mass of sodium thiosulfate pentahydrate, Na2S2O3•5H20. What is the molarity of Na2S2O3 in this solution at 20°C? The density of this solution at 20°C is 1.176 g/mL.
Molarity = mol/L

just did the assignment and the answer was #1 +2 n

c is having 4 valence electrons and is bonded to three hydrogens and one sulphur atom, therefore, the number of bond pair is equal to four. as all the valence electrons are used in forming the bonds so, there is no lone pair left on carbon.

s is having 6 valence electrons and is bonded to one other sulfur atom and one carbon atom, therefore, the number of bond pair is equal to 2. as only two valence electrons are used in forming the bonds so, four electrons are left. therefore, two lone pairs are present on s.