help Will Fe Fe2 or Fe3 react more favorably with CO Why One

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Will Fe, Fe2+, or Fe3+ react more favorably with CO? Why? One of the possible sources of toxicity of mercury in the body is competitive binding to the thiol (-SH) residue of cysteine that is normally a site for Zn2+ binding. Why does mercury compete and win for binding to these sites when there is far more zinc in the human body? Explain why dimethyl- or diphenyl mercury are VERY toxic when introduced into the body, but we can hold liquid mercury in our hand (with small amounts that do get absorbed) and there is little to no toxicity. Ignore absorption issues.

Solution

a) Fe3+ has high positive charge, so is expected to be a hard acid and hence reacts more favorably with CO

b) The mercury atom or molecule will tnd to bind with any molecule present that has sulphur or a sulphur- hydrogen combo in its structure. This process of combining with a metal to form a complex in which the metallic ion is sequestered and firmly bound is called chelation. A thiol is any organic compound containing a univalent radical called a sulfhydryl and identified by the symbol -SH (sulfur-hydrogen)

high levels of methylmercury or phenylmercury in laboratory studies experienced damage to the kidneys, stomach, and large intestine; changes in blood pressure and heart rate; adverse effects on the developing fetus, sperm, and male reproductive organs; and increases in the number of spontaneous abortions and stillbirths. Adverse effects on the nervous system of animals occur at lower doses than do harmful effects to most other systems of the body. This difference indicates that the nervous system is more sensitive to methylmercury toxicity than are other organs in the body. Animal studies also provide evidence of damage to the nervous system from exposure to methylmercury during development, and evidence suggests that the effects worsen with age, even after the exposure stops