Question

How many hydrogen molecules are needed for complete catalytic hydrogenation of 0.5 moles of thetricylglycerol which forms glycerol, palmitic acid, oleic acid and linoleic acid by hydrolysis?

Answer 1

n(C₁₅H₃₁COOH) = 0.5 mol.

n(C₁₇H₃₃COOH) = 0.5 mol.

n(C₁₇H₃₁COOH) = 0.5 mol.

C₁₅H₃₁COOH + H₂ ≠

   0.5mol        Xmol

C₁₇H₃₃COOH + H₂ = C₁₇H₃₅COOH

      1mol         1mol

n₁(H₂) = X = 0.5 mol.

   0.5mol        Ymol

C₁₇H₃₁COOH + 2H₂ = C₁₇H₃₅COOH

      1mol         2mol

n₂(H₂) = X = 1 mol.

n(H₂) = n₁(H₂) + n₂(H₂) = 0.5 mol + 1 mol = 1.5 mol.

N(H₂) = n(H₂) × N_A = 1.5 mol × 6.02 × 10²³ mol^-1 = 9.03 × 10²³.