MCQEasyJEE 2023Group 18 Elements

JEE Chemistry 2023 Question with Solution

XeF4_4 reacts with SbF5_5 to form: [XeFm]n+[SbFy]z[XeF_m]^{n+}[SbF_y]^{z-} What is m+n+y+zm+n+y+z?

  • A

    1010

  • B

    1111

  • C

    1212

  • D

    1313

Answer

Correct answer:B

Step-by-step solution

Standard Method

Given: XeF4_4 reacts with SbF5_5 to form [XeFm]n+[SbFy]z[XeF_m]^{n+}[SbF_y]^{z-}.

Find: The value of m+n+y+zm+n+y+z.

From the reaction shown in the solution:

XeF4+SbF5[XeF3]++(SbF6)\text{XeF}_4 + \text{SbF}_5 \to [\text{XeF}_3]^+ + (\text{SbF}_6)^-

So, comparing with [XeFm]n+[SbFy]z[XeF_m]^{n+}[SbF_y]^{z-}:

  • m=3m = 3
  • n=1n = 1
  • y=6y = 6
  • z=1z = 1

Therefore,

m+n+y+z=3+1+6+1=11m+n+y+z = 3+1+6+1 = 11

The correct option is B.

Common mistakes

  • Taking the cation as [XeF4]+[\text{XeF}_4]^+ is incorrect because the extracted reaction in the solution shows formation of [XeF3]+[\text{XeF}_3]^+. Use the species actually given in the reaction before assigning mm and nn.

  • Ignoring the magnitude of charge on the ions is wrong because nn and zz come from the superscripts. Here the ions are +1+1 and 1-1, so both nn and zz are counted as 11 in the sum.

  • Using SbF5\text{SbF}_5^- for the anion is incorrect. Antimony pentafluoride accepts an extra fluoride to form [SbF6][\text{SbF}_6]^-, so y=6y=6, not 55.

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