3-Methylbut-1-ene is converted to an alcohol in three separate ways: (1) Hg(OAc)2, H2O then NaBH4; (2) dilute H2SO4; (3) BH3.THF then H2O2/NaOH. Each alcohol is then treated with warm acidified K2Cr2O7. Which alcohols are oxidised?

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JEE Advanced levelSingle correct optionDifficulty 3 of 3o2206

3-Methylbut-1-ene is converted to an alcohol in three separate ways: (1) $Hg (OAc) X_{2}, H X_{2} O$ then $NaBH X_{4}$ ; (2) dilute $H X_{2} SO X_{4}$ ; (3) $BH X_{3} \cdot THF$ then $H X_{2} O X_{2} / NaOH$ . Each alcohol is then treated with warm acidified $K X_{2} Cr X_{2} O X_{7}$ . Which alcohols are oxidised?

Athat from (2) only
Bthose from (1) only
Cthose from (1), (2) and (3)
Dthose from (1) and (3) only

Answer: D

(1) gives 3-methylbutan-2-ol, a secondary alcohol, which is oxidised to a ketone. (2) gives 2-methylbutan-2-ol, tertiary, which is not oxidised. (3) gives 3-methylbutan-1-ol, primary, which is oxidised. So (1) and (3) are oxidised.

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3-Methylbut-1-ene is converted to an alcohol in three separate ways: (1) Hg(OAc)X2​,HX2​O then NaBHX4​; (2) dilute HX2​SOX4​; (3) BHX3​⋅THF then HX2​OX2​/NaOH. Each alcohol is then treated with warm acidified KX2​CrX2​OX7​. Which alcohols are oxidised?

Answer: D

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