What volume of 1 M NaOH (in ml) will be required to react completely with 100g of oleum which is 109% labelled?
109% oleum means that 9g of H2O is required to convert all SO3 present in 100g of it to H2SO4.
SO3 + H2O → H2SO4
1 mole (80g) of SO3 reacts with 1 mole (18g) of H2O
So 40g of SO3 will react with 9g of H2O.
According to the following equation, 80g of NaOH will react with 80g and 98g of SO3 and H2SO4 respectively.
SO3 + 2NaOH → Na2SO4 + H2O
H2SO4 + 2NaOH → Na2SO4 + 2H2O
Wt. of SO3 present in 100g of the oleum sample = 40g
Wt. of H2SO4 present in 100g of the oleum sample = (100 – 40)g = 60g
Wt. of NaOH required to completely neutralize 40g of SO3 = (80x40)/80 = 40g
Wt. of NaOH required to completely neutralize 60g of H2SO4 = (80x60)/98 = 48.98g
Total Wt. of NaOH required for complete neutralization = 40 + 48.98 = 88.98g
Volume of 1M NaOH solution containing 88.98g of NaOH = (1000x88.98)/40 = 2224.5mL