Question

# Ethanal CH3CHO, can be produced from a mixture of carbon monoxide and hydrogen, by way of the following reaction: 2 \mathrm{CO}(\mathrm{g})+\mathrm{BH} 2(\mathrm{~g})=\mathrm{CH} 3 \mathrm{CHO}(\mathrm{g})+\mathrm{H} 2 \mathrm{O}(\mathrm{g}) (a) According to thermodynamic arguments and taking any necessary information from the S315 Data table Thermodynamic data at 298.15 K',would the equilibrium yield of ethanol increase or decrease if: (i) the pressure was increased, (ii) the temperature was increased? Include your reasoning and calculations in your answer. (i) Define the equilibrium yield, y, of ethanal CH2CHO from Reaction 1.1.Hence, show that the partial pressure of CO, (p(CO)) and H2 (p(H2)) in the equilibrium mixture for Reaction 1.1 can be expressed as: p(\mathrm{CO})={ }^{\frac{2}{5}} p_{\mathrm{mon}}(1-2 y) p\left(\mathbf{H}_{2}\right)={ }^{\frac{3}{5}} p_{\mathrm{tot}}(1-2 y) where pot is the total pressure of the equilibrium mixture. State any assumptions you make in your derivation. (ii) Write down an expression for the equilibrium constant, Kp, for Reaction1.1 in terms of the partial pressures of the substances involved. Hence,show that the expression takes the form: K_{p}=\left\{\frac{3125 y^{2}}{108(1-2 y)^{5}}\right\} \times \frac{1}{p_{\mathrm{tot}}^{3}} where y is the equilibrium yield of ethanal and ptot is the total pressure. (iii) Using Equation 1.2 and assuming an overall pressure (pot) Oof 1 bar,determine Kp and hence K°, at which the equilibrium yield of ethanal will be 40% (that is, y = 0.40).  Fig: 1  Fig: 2  Fig: 3  Fig: 4  Fig: 5  Fig: 6  Fig: 7  Fig: 8  Fig: 9  Fig: 10  Fig: 11  Fig: 12  Fig: 13  Fig: 14