UPSEE Solved Model Paper 4

Moles of H2SO4 =

100+x

98

Moles of Ca(OH)2 taken = 2.75 × 0.5 = 1.375
Moles of H3PO3 used =

15.7

82

Since H3PO3 is dibasic
∴ moles of Ca(OH)2 left =

15.7

82

∴ Moles of Ca(OH)2 used with H2SO4 = 1.375 -

15.7

82

∴

100+x

98

= 1.375 -

15.7

82

Solving x = 15.64
∴ SO2 =

15.64

18

× 80 = 71.1 g