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7. What is the carbon source in the benzimidazole structure?

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8. What is the carbon source in 2-methyl benzimidazole synthesis?
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9. Mention one commercial drug containing benzimidazole nucleus & its uses.
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10. Calculate the needed amounts to do the reaction (in gram for solid & ml for liquid)
of 0.008 moles of o-phenylenediamine and 0.012 moles of formic acid, then calculate
the theoretical yield.

(M.Wt. of o-phenylenediamine = 108.14 g)
(M.Wt. of formic acid = 46.03 g)
(M.Wt. of benzimidazole = 118.14 g)

o-phenylenediamine Formic acid Theoretical yield
amount (g) amount (ml)

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11. In the previous example, if the weight of the pure dry powder benzimidazole was

0.5 gram, calculate the %yield.
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