Ethyne or acetylene can be hydrogenated to change from the triple bonded C2H2 to the double-bonded C2H4. Adding hydrogens in organic chemistry is called reduction. Adding and removing hydrogens are important steps in chemical manufacturing. Calculate the value of ΔS° for the catalytic hydrogenation of acetylene to ethene,

C2H2 (g) + H2 (g) --> C2H4 (g)


A. +18.6 J/mol K

B. -18.6 J/mol K

C. -112.0 J/mol K

D. +112.0 J/mol K