In the contact process, the SO3 formed is absorbed in concentrated H2SO4 and not directly in water because

direct absorption in water forms a fine acid mist that is difficult to condense; absorption in conc. H2SO4 gives oleum, which is then diluted

water would reduce SO3 back to SO2

oleum is the only product wanted and cannot be diluted

JEE Main levelSingle correct optionDifficulty 2 of 3pn081

In the contact process, the $SO X_{3}$ formed is absorbed in concentrated $H X_{2} SO X_{4}$ and not directly in water because

Adirect absorption in water forms a fine acid mist that is difficult to condense; absorption in conc. $H X_{2} SO X_{4}$ gives oleum, which is then diluted
Bwater would reduce $SO X_{3}$ back to $SO X_{2}$
C $SO X_{3}$ does not react with water
Doleum is the only product wanted and cannot be diluted

SO X_{3} + H X_{2} O

is highly exothermic and forms a mist of

H X_{2} SO X_{4}

droplets. Dissolving

SO X_{3}

in 98% acid gives oleum (

H X_{2} S X_{2} O X_{7}

), which is diluted with water to the required acid concentration.