An aliphatic compound [X], Molecular formula ( C ₄ H ₁₀ O ) can be prepared from Acetone and R– Mg–X. [X] with 20% Phosphoric acid gives an unsaturated compound C ₄ H ₈ [Y]. Compound [Y] is also obtained on heating [X] with Copper metal at 573K. [X] shows no reaction with PCC but on heating with acidified KMnO ₄ it forms Acetone + CO ₂ + H ₂ O . Compounds [X] and [Y] are -------------------- and --------------------

Step-by-step solution

Acetone ( CH ₃ COCH ₃ ) reacts with methylmagnesium halide ( CH ₃ MgX ) followed by hydrolysis to form a tertiary alcohol, 2-methylpropan-2-ol. CH ₃ COCH ₃ + CH ₃ MgX ( CH ₃)₃ C-OH Thus, compound [X] is 2-methylpropan-2-ol, which has the molecular formula C ₄ H ₁₀ O . Dehydration of [X] with 20% H ₃ PO ₄ or heating with Cu at 573 K yields 2-methylpropene [Y]. ( CH ₃)₃ C-OH ( CH ₃)₂ C=CH ₂ + H ₂ O Tertiary alcohols do not undergo oxidation with PCC, hence [X] shows no reaction. Vigorous oxidation of [X] with acidifi