Question

( mathrm{SO}_{3}+mathrm{H}_{2} mathrm{O} rightarrow mathrm{H}_{2} mathrm{SO}_{4} )
( mathrm{x} / 80 mathrm{mole} ) of ( mathrm{SO}_{3} ) produces ( mathrm{x} / 80 mathrm{mole} )
of ( mathrm{H}_{2} mathrm{SO}_{4} )
weight of ( mathrm{H}_{2} mathrm{SO}_{4}=mathrm{x} / 80^{star} 98 )
Total weight of ( mathrm{H}_{2} mathrm{SO}_{4} ) present in solution after dilution ( x / 80^{star} 98+(100-x)=104.5 )
( x=20 mathrm{g} )
Therefore, %age of free ( mathrm{SO}_{3} ) is ( 20 % ).

# (3) 10.5 (4) 0.5 In a given sample, oleum is labelled as 104.5%. The percentage of free Soz in it is (1) 4.5% (2) 10% (3) 20% (4) 40% 81. Weight of Na coz of 80% purity would be required

Solution