Question

12dm3 ethene reacts with steam to make 18.4g ethanol.find the percentage yield

Answer 1

% yield = 74.35

Further explanation

Given

12 dm³ ethene = 12 L

18.4 g ethanol(actual)

Required

The percentage yield

Solution

Reaction

C₂H₄(g) + H₂O(g) ⇒ C₂H₅OH(g)

Assume at STP, 1 mol gas = 22.4 L

mol ethene :

= 12 L : 22.4 L

= 0.538

From equation, mol ratio C₂H₅OH : C₂H₄ = 1 : 1, so mol C₂H₅OH = 0.538

Mass Ethanol (MW=46 g/mol) ⇒ theoretical

= 0.538 x 46

= 24.748 g

% yield = (actual/theoretical) x 100%

% yield = (18.4/24.748) x 100%

% yield = 74.35