question_answer

5 moles of \[S{{O}_{2}}\] and 5 moles of \[{{O}_{2}}\] are allowed to react to form \[S{{O}_{3}}\] in a closed vessel. At the equilibrium stage 60% of \[S{{O}_{2}}\] is used up. The total number of moles of \[S{{O}_{2}}\], \[{{O}_{2}}\] and \[S{{O}_{3}}\] in the vessel now is

A) 10.0

B) 8.5

C) 10.5

D) 3.9