But-2-yne is reacted separately with one mole of Hydrogen as shown below: (B) NH . liq Na 3 H CH – C — JEE Mains Chemistry Past Papers Chemistry Question
Question
But-2-yne is reacted separately with one mole of Hydrogen as shown below: (B) NH . liq Na 3 H CH – C C – CH C / Pd (A) A. A is more soluble than B. B. The boiling point & melting point of A are higher and lower than B respectively. C. A is more polar than B because dipole moment of A is zero. D. Br2 adds easily to B than A. Identify the incorrect statements from the options given below: (A) A, C & D only (B) A and B only (C) B, C & D only (D) B and C only
💡 Solution & Explanation
Physical properties H3C C = C H H B CH3 =0 H3C C = C H H A CH3 0 Remarks Dipole moment A > B cis-isomer has resultant of dipoles while in trans isomer dipole moments cancel out Boiling point A > B Molecules having higher dipole moment have higher boiling point due to larger intermoleculer force of attraction Solubility (in H2O) A > B More polar molecules are more soluble in H2O. Melting point B > A More symmetric isomers have higher melting points due to better packing in crystalline lattice & trans isomers are more symmetric than cis. The correct answer should be (C) and (D) only.