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Illustrative is the preparation of phenyllithium from bromobenzene using n-butyllithium (n-BuLi): C 6 H 5 Br + BuLi → C 6 H 5 Li + BuBr Direct formation of Grignard reagents , by adding the magnesium to the aryl halide in an ethereal solution, works well if the aromatic ring is not significantly deactivated by electron-withdrawing groups.
The Sandmeyer reaction is an example of a radical-nucleophilic aromatic substitution (S RN Ar). The radical mechanism of the Sandmeyer reaction is supported by the detection of biaryl byproducts. [8]
They are a subset of the general class of halocarbons, although the distinction is not often made. Haloalkanes are widely used commercially. Haloalkanes are widely used commercially. They are used as flame retardants , fire extinguishants , refrigerants , propellants , solvents , and pharmaceuticals .
Oswaal Books is an Indian educational publishing company headquartered in Agra, India.Established in 1984 by Naresh Jain, the company focuses on producing study materials for different educational boards, including CBSE, ISC, ICSE, and Karnataka, as well as materials for competitive exams such as JEE Main and Advanced, NEET, CAT, and CLAT. [1]
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From January 2020 onwards, an additional Paper-III is being introduced for B.Planning courses separately. [4] Due to the COVID-19 pandemic in 2020, JEE-Main 2021 has a change in paper format and number of attempts. Now there will be 20 single choice questions and 10 numerical questions out of which only five numerical questions are to be attempted.
Unlike most of the other exams, the type, the number of questions being asked in the paper, the total marks and the marking scheme varies from year to year depending upon the organizing institute, with an average of about 36–38 questions asked from each subject across both the papers. For example, the 2021 JEE-Advanced paper had 38 questions ...
The latest structure includes two sections, i.e. A and B, in all four subjects, namely Physics, Chemistry, Botany, and Zoology. Section A comprises 35 mandatory questions, while Section B contains 15 questions, out of which 10 questions are to be answered, leading to a total of 200 questions, with 180 questions that can be answered. [19]