catalyst gets poisoned
In catalysis, if a molecule forms strong bonds to the catalyst, then the catalyst may become poisoned. Experiments on various catalysts showed the following results: a. Fe, Ru, and Os form weak bonds with N2; however, O2, alkynes, alkenes, CO, H2, and CO2 interact more strongly. CO2 and H2 form weak bonds with a Co or Ni surface. Rh, Pd, Ir, and Pt form weak bonds with H2 but do not bond with CO2. Cu, Ag, and Au form weak bonds with CO and ethylene. Explain why Fe was chosen as a catalyst to convert nitrogen and hydrogen to ammonia. Why is Fe more suitable than Ru or Os? f. Because alkenes generally interact more strongly with metal surfaces than does H 2, what catalyst would you choose for hydrogenation of an alkene such as ethylene? g. Although platinum is used in catalytic converters for automobile exhaust, it was not found to be a particularly effective catalyst for the reaction of H2 with a mixture of carbon monoxide and carbon dioxide to produce methane. Why? h. If you were interested in developing a catalyst to reversibly bind ethylene, which of the catalysts listed here would you choose? 14. Nonstoichiometric metal oxides can be effective catalysts for oxidationreduction reactions. One such catalyst is Ni1xO, found to be effective for converting CO to CO2when oxygen is present. Why is it so effective? 15. The chemical reactions in an organism can be controlled by regulating the activity of certain enzymes. Efficient regulation results in an enzyme being active only when it is needed. For example, if a cell needed.