MyCompetitiveExams Dynamic 180-question full-length simulator mixed dynamically from all 6 years for 2027 & 2026 aspirants.
The products A and B obtained in the following reactions, respectively, are 3ROH + PCl₃ → 3RCl + A; ROH + PCl₅ → RCl + HCl + B
PCl3 gives phosphorous acid (H3PO3)! PCl5 gives phosphorus oxychloride (POCl3)! Look for (H3PO3 and POCl3) -> Option (2)!
Phosphorus trichloride possesses phosphorus in the +3 oxidation state. Nucleophilic attack by three molecules of alcohol displaces all three chloride atoms in sequence, producing three moles of alkyl chloride and one mole of orthophosphorous acid (H3PO3):
Phosphorus pentachloride possesses phosphorus in the +5 oxidation state. The alcohol oxygen coordinates to phosphorus, releasing HCl and collapsing through a four-membered transition state to form one mole of alkyl chloride and one mole of phosphoryl chloride / phosphorus oxychloride (POCl3):
Product A is H3PO3 (phosphorous acid), and Product B is POCl3 (phosphoryl chloride). This pairing uniquely matches Option (2).
Diagnose every choice: Know exactly why the right option works and why distractors fail.
Product A is H3PO3, not H3PO4 (phosphoric acid requires +5 phosphorus).
Exact stoichiometric by-products for PCl3 and PCl5 reactions with alcohols.
Inverts the identity of A and B.
Both products incorrectly identified.
PCl3 has P(+3), so it forms H3PO3 (phosphorous acid with P in +3). It CANNOT form H3PO4 (phosphoric acid with P in +5) without an oxidizing agent!
"Alcohols react with PCl3 to give RCl and H3PO3; alcohols react with PCl5 to give RCl, HCl, and POCl3."
Test your speed and accuracy in the authentic 200-minute timed NTA simulator.
Spotted a mistake in this solution? Report an error (support@mycompetitiveexams.com)
Cover all 1,140 official NEET questions in 285 days at your own pace. Progress is saved on your device. No login needed.