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Haloalkanes and Haloarenes — Chemistry STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceChemistryHaloalkanes and Haloarenes5 Marks
Question

Identify A, B, C, D, E, R and $R^1$ in the following:
✓

Answer



Since D of D2O gets attached to the carbon atom to which MgBr is attached, C is
$\text{CH}_3\text{CHCH}_3\\\ \ \ \ \ \ \ \ \ |\\\ \ \ \ \ \ \ \text{MgBr}\\\text{Isopropylmagnesium bromide}$
Therefore, the compound R - Br is
$\text{CH}_3\text{CHCH}_3\\\ \ \ \ \ \ \ \ \ |\\\ \ \ \ \ \ \ \text{Br}\\2-\text{Bromopropane}$
$\text{CH}_3\text{CHCH}_3+\text{Mg}\xrightarrow[]{\text{dry ether}}\text{CH}_3\text{CHCH}_3\xrightarrow[]{\text{D}_2\text{O}}\text{CH}_3\text{CHCH}_3\\\ \ \ \ \ \ \ \ \ |\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ |\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ |\\\ \ \ \ \ \ \ \ \text{Br}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{MgBr}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{D}\\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ (\text{C})$
When an alkyl halide is treated with Na in the presence of ether, a hydrocarbon containing double the number of carbon atoms as present in the original halide is obtained as product. This is known as Wurtz reaction. Therefore, the halide, R1-X, is
$\ \ \ \ \ \ \ \ \ \ \ \text{CH}_3\\\ \ \ \ \ \ \ \ \ \ \ \ \ |\\\text{CH}_3-\text{C}-\text{X}\\\ \ \ \ \ \ \ \ \ \ \ \ \ |\\\ \ \ \ \ \ \ \ \ \ \ \text{CH}_3\\\ \text{tert}-\text{Butylhalide}$
Therefore, compound D is
$\ \ \ \ \ \ \ \ \ \ \ \text{CH}_3\\\ \ \ \ \ \ \ \ \ \ \ \ \ |\\\text{CH}_3-\text{C}-\text{MgBr}\\\ \ \ \ \ \ \ \ \ \ \ \ \ |\\\ \ \ \ \ \ \ \ \ \ \ \text{CH}_3\\\ \text{tert}-\text{Butylmagnesiumbromide}$
And, compound E is
$\ \ \ \ \ \ \ \ \ \ \ \text{CH}_3\\\ \ \ \ \ \ \ \ \ \ \ \ \ |\\\text{CH}_3-\text{C}\\\ \ \ \ \ \ \ \ \ \ \ \ \ |\\\ \ \ \ \ \ \ \ \ \ \ \text{CH}_3\\2-\text{Methylpropane}$

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