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For the estimation of nitrogen, 1.4 g of an organic compound was diagesed by Kjeldahl method and the evolved ammonia was absorbed in 60 mL of M/10 sulphuric acid. The unreacted acid required 20 mL of M/10 sodium hydroxide for complex neutralization. The percentage of nitrogen in the compound is |
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Answer» `6%` let it CONTAIN X m mole of N atom. `" Oraganic compund " RARR underset(" X m mole")(NH_(5))` `2NH_(3) + underset(" intitally taken") underset(6m " mole")(H_(2)SO_(4)) rarr(NH_(4))_(2)SO_(4)(1st)` `underset("REACTED")underset(" 2 m mole")(H_(2)SO_(4) + 2 NaOH) rarr Na_(2)SO_(4)+2H_(2)O(2nd)` Hence m moles of `H_(2)SO_(4)` reacted in 2nd EQUATION = 1 `rArr ` m moles of `H_(2)SO_(4)` reacted from 1st equation `= 6- 1= 5 m` moles `rArr ` m moles of `NH_(3)` in 1st equation `= 2 xx 5 = 10 m` moles `rArr m` moles of N atom in the organic compound `= 10m` moles `rArr` mass of `N = 10 xx 10^(-3) xx 14 = 0.14 g` `rArr %` of `N = (0.4)/(1.4) xx 100 = 10%` |
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