{"id":664,"date":"2010-11-29T11:10:34","date_gmt":"2010-11-29T19:10:34","guid":{"rendered":"http:\/\/wordpress.reed.edu\/chem201202\/2010\/11\/hg-free-exams-not-quite.html"},"modified":"2014-03-18T10:13:02","modified_gmt":"2014-03-18T17:13:02","slug":"hg-free-exams-not-quite","status":"publish","type":"post","link":"https:\/\/blogs.reed.edu\/chem201202\/2010\/11\/hg-free-exams-not-quite\/","title":{"rendered":"Hg-free Exams? Not quite"},"content":{"rendered":"<p>Homework assignment #6 contained an important announcement, but many students who worked on the homework either ignored the announcement or didn&#8217;t fully understand it (and many students may not have even seen the announcement given the small number of completed assignments that were turned in).<\/p>\n<p>Here&#8217;s the announcement quoted in its entirety and verbatim:<\/p>\n<blockquote><p><i><b>Reagent Alert:<\/b><\/i> I will not cover, and <i>I am not going to test you on<\/i>, the chemistry of <b>Hg(OAc)2 + H2O, then NaBH4<\/b>, but Loudon uses this reagent extensively in practice problems. Every time you run into this reagent, simply substitute another reagent in its place: <b>H2O + cat. H2SO4<\/b>.<\/p><\/blockquote>\n<p>And here&#8217;s what I saw on HW #6:<\/p>\n<ul>\n<li>occasionally replacement of the entire oxymercuration-reduction reagent with H2O + cat. H2SO4 (correct behavior)<\/li>\n<li>more often, replacement of parts of the oxymercuration-reduction reagent with H2O + cat. H2SO4. This is incorrect. Do not draw hybrid reagents like &#8220;H2O + cat. H2SO4 then NaBH4&#8221;. In fact, do not resort to oxymercuration-reduction in this class at all.<\/li>\n<\/ul>\n<p>But that&#8217;s not all. This reagent-alert does not mean that you should never draw Hg-containing reagents. The <a href=\"https:\/\/blogs.reed.edu\/chem201202\/files\/2010Lectures\/Activity%2033%20H2O%20alkyne%20addition.pdf\"><b>activity<\/b><\/a> for <b>class #33 &#8211; Alkyne addition reactions: hydrohalogenation and hydration<\/b> describes the use of salts containing Hg+2 as a method for promoting hydration of alkynes.<\/p>\n<p><b>Bottom-line:<\/b> draw H2O + cat. H2SO4 to hydrate alkenes (Markovnikov) and draw H2O + Hg+2 + H2SO4 to hydrate alkynes (Markovnikov). <\/p>\n","protected":false},"excerpt":{"rendered":"<p>Homework assignment #6 contained an important announcement, but many students who worked on the homework either ignored the announcement or didn&apos;t fully understand it (and many students may not have even seen the announcement given the small number of completed&#8230;<\/p>\n","protected":false},"author":55,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8,9],"tags":[],"class_list":["post-664","post","type-post","status-publish","format-standard","hentry","category-exams","category-homework"],"_links":{"self":[{"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/posts\/664","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/users\/55"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/comments?post=664"}],"version-history":[{"count":2,"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/posts\/664\/revisions"}],"predecessor-version":[{"id":5120,"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/posts\/664\/revisions\/5120"}],"wp:attachment":[{"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/media?parent=664"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/categories?post=664"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.reed.edu\/chem201202\/wp-json\/wp\/v2\/tags?post=664"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}