{"id":180674,"date":"2025-01-08T14:48:10","date_gmt":"2025-01-08T14:48:10","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=180674"},"modified":"2025-01-08T14:48:14","modified_gmt":"2025-01-08T14:48:14","slug":"the-bh2-ion-diagram-is-for-the-lewis-structure-with-the-hydrogens-pointing-straight-up","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/01\/08\/the-bh2-ion-diagram-is-for-the-lewis-structure-with-the-hydrogens-pointing-straight-up\/","title":{"rendered":"The BH2+ ion diagram is for the Lewis structure with the hydrogens pointing straight up"},"content":{"rendered":"\n

The BH2+ ion diagram is for the Lewis structure with the hydrogens pointing straight up, and is correct. How would the diagram look when the H’s are rotated 90 degrees? Rank the SN2 reaction rates for the following compounds: iodomethane 3-iodo-2-methylhexane 1-iodo-2-methylhexane 2-iodo-2-methylhexane<\/p>\n\n\n\n

The Correct Answer and Explanation is :<\/strong><\/mark><\/p>\n\n\n\n

BH\u2082\u207a Ion Diagram with Hydrogens Rotated 90 Degrees<\/h3>\n\n\n\n

The BH\u2082\u207a ion has a trigonal planar geometry because boron typically forms three bonds and lacks a complete octet in this ion. If the hydrogens in the correct Lewis structure (pointing straight up) are rotated 90 degrees, the diagram would resemble a flat triangle where the boron atom is at the center and the hydrogens are aligned in a plane at a 90-degree angle relative to the original orientation. This rotation does not change the bond angles (120\u00b0) because trigonal planar geometry inherently maintains the angles regardless of rotation.<\/p>\n\n\n\n

\n\n\n\n

Ranking SN2 Reaction Rates<\/h3>\n\n\n\n

Compounds:<\/strong><\/p>\n\n\n\n

    \n
  1. Iodomethane (CH\u2083I)<\/strong><\/li>\n\n\n\n
  2. 3-iodo-2-methylhexane<\/strong><\/li>\n\n\n\n
  3. 1-iodo-2-methylhexane<\/strong><\/li>\n\n\n\n
  4. 2-iodo-2-methylhexane<\/strong><\/li>\n<\/ol>\n\n\n\n

    Correct Order of Reaction Rates (Fastest to Slowest):<\/strong><\/p>\n\n\n\n

      \n
    1. Iodomethane (CH\u2083I)<\/strong><\/li>\n\n\n\n
    2. 1-iodo-2-methylhexane<\/strong><\/li>\n\n\n\n
    3. 3-iodo-2-methylhexane<\/strong><\/li>\n\n\n\n
    4. 2-iodo-2-methylhexane<\/strong><\/li>\n<\/ol>\n\n\n\n
      \n\n\n\n

      Explanation<\/h3>\n\n\n\n

      The SN2 (bimolecular nucleophilic substitution)<\/strong> reaction depends on two factors:<\/p>\n\n\n\n

        \n
      1. Steric Hindrance<\/strong>: The bulkier the substituents around the electrophilic carbon, the slower the reaction rate.<\/li>\n\n\n\n
      2. Leaving Group Ability<\/strong>: Iodine (I\u207b) is an excellent leaving group, so differences in rates arise primarily due to steric hindrance.<\/li>\n<\/ol>\n\n\n\n
          \n
        • Iodomethane (CH\u2083I)<\/strong> has minimal steric hindrance because the electrophilic carbon is only bonded to hydrogens, making it the fastest to react.<\/li>\n\n\n\n
        • 1-iodo-2-methylhexane<\/strong> has moderate hindrance as the electrophilic carbon is attached to a primary carbon chain with a single branching.<\/li>\n\n\n\n
        • 3-iodo-2-methylhexane<\/strong> is more hindered than 1-iodo-2-methylhexane because the iodine is attached to a secondary carbon with more branching in proximity.<\/li>\n\n\n\n
        • 2-iodo-2-methylhexane<\/strong> has the slowest reaction rate because the iodine is on a tertiary carbon, causing significant steric hindrance.<\/li>\n<\/ul>\n\n\n\n

          Thus, the reaction rate decreases as the steric hindrance around the electrophilic carbon increases.<\/p>\n","protected":false},"excerpt":{"rendered":"

          The BH2+ ion diagram is for the Lewis structure with the hydrogens pointing straight up, and is correct. How would the diagram look when the H’s are rotated 90 degrees? Rank the SN2 reaction rates for the following compounds: iodomethane 3-iodo-2-methylhexane 1-iodo-2-methylhexane 2-iodo-2-methylhexane The Correct Answer and Explanation is : BH\u2082\u207a Ion Diagram with Hydrogens […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-180674","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/180674","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=180674"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/180674\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=180674"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=180674"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=180674"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}