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JEE Advanced levelOne or more correct optionsDifficulty 3 of 3hx012

4-Methylaniline is diazotised with $NaNO X_{2}$ and $HCl$ at 273-278 K to give 4-methylbenzenediazonium chloride. Which of the following transformations of this salt are correct?

A $CuBr$ with $HBr$ gives 1-bromo-4-methylbenzene.
B $KI$ gives 1-iodo-4-methylbenzene.
C $HBF X_{4}$ , then heating the isolated salt, gives 1-fluoro-4-methylbenzene.
D $H X_{3} PO X_{2}$ gives 1-chloro-4-methylbenzene.

Answer: A, B, C

Cu(I) bromide gives the aryl bromide (Sandmeyer),

KI

displaces

N X_{2}

without any copper, and the tetrafluoroborate salt decomposes to the aryl fluoride (Balz-Schiemann).

H X_{3} PO X_{2}

is a reducing agent that replaces

N X_{2} X^{+}

by

H

and gives toluene, not a chlorotoluene.

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