Page 13 - Practical-organic-3

Sec 1: Synthesis of Benzimidazole

Calculations: ⸪ One mole of any substance = Molecular weight in grams

Amount of o- Amount of formic acid Amount of benzimidazole (g)
phenylenediamine (g) (ml) (Theoretical Yield)
1 mole → 108.14 g 1 mole → 46.03 g 1 mole → 118.14 g

0.01 mole → ? 0.02 mole → ? 0.01 mole → ?

⸫ o-Phenylenediamine Amount = 0.92 g ⸫ Benzimidazole amount
(theoretical yield) = 1.18 g
amount = 1.08 g As formic acid is liquid,

⸪ Density of formic acid
◼ o-Phenylenediamine

is the limiting = ρ = m (grams) %Yield =
reactant which is ( ) ( )
used up first. = 1.22 g/ml ( ) ×
= ⋯ %
m (g)
⸫ ( ) = ( ) ×
ρ (ml)
. ( )
0.92 = ⋯ %
=
1.22

⸫
= . ≅ .

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