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← JEE Advanced 2019 · Paper 2
ChemistryMultiple correct+4 / -1Question 21 of 54

JEE Advanced 2019 · Paper 2, Chemistry question 3

Consider the following reactions (unbalanced)

Zn\ce{Zn} + hot conc. HX2SOX4→\ce{H2SO4} \to G + R + X

Zn\ce{Zn} + conc. NaOH→\ce{NaOH} \to T + Q

G + HX2S\ce{H2S} + NHX4OH→\ce{NH4OH} \to Z (a precipitate) + X + Y

Choose the correct option(s)

Choose one or more options
Answer and worked solution

Official answer: A, C, D

Identify the species.

  • Zn+2 HX2SOX4→ZnSOX4+SOX2+2 HX2O\ce{Zn + 2H2SO4 -> ZnSO4 + SO2 + 2H2O}, so G is ZnSOX4\ce{ZnSO4}, R is SOX2\ce{SO2} and X is HX2O\ce{H2O}.
  • Zn+2 NaOH→NaX2ZnOX2+HX2\ce{Zn + 2NaOH -> Na2ZnO2 + H2}, so T is NaX2ZnOX2\ce{Na2ZnO2} and Q is HX2\ce{H2}.
  • ZnSOX4+HX2S+2 NHX4OH→ZnS↓+(NHX4)X2SOX4+2 HX2O\ce{ZnSO4 + H2S + 2NH4OH -> ZnS v + (NH4)2SO4 + 2H2O}, so Z is ZnS and Y is (NHX4)X2SOX4\ce{(NH4)2SO4}.

The statements.

  • (A) ZnS is (dirty) white. True.
  • (B) Zn is +2 in sodium zincate. False.
  • (C) SOX2\ce{SO2} is bent. True.
  • (D) HX2\ce{H2} has bond order 1. True.

(A), (C), (D)