Chemistry - Complete P-block Question with Solution | TestHub
Identify the principal products X, Y and Z of the following reactions : (i) P₄ + limited Cl₂ → (X) ; (ii) P₄ + excess dry Cl₂ → (Y) ; (iii) P₄ + hot conc. NaOH + H₂O → PH₃ + (Z). Which of the following statements about X, Y and Z is CORRECT?
Options:
Answer:
Solution:
X = PCl₃, Y = PCl₅, Z = NaH₂PO₂. (A) CORRECT : PCl₅ + 2Ag PCl₃ + 2AgCl (metals reduce PCl₅ to PCl₃). (B) Wrong : the actual disproportionation of hypophosphite on heating is 2NaH₂PO₂ → Na₂HPO₄ + PH₃ - phosphorus is oxidised all the way to hydrogen PHOSPHATE (P +5), not to phosphite (the phosphite equation does not even balance in oxygen). (C) Wrong : NaH₂PO₂ is the salt of a WEAK acid (H₃PO₂) and a strong base, so its solution is basic. (D) Wrong : P in PCl₃ carries exactly ONE lone pair (pyramidal, sp³).
