Periodic Table · JEE Main previous year questions

2018 2 questions

1. Q872018 · 16 Apr 2018 · Shift 1

   A group 13 element 'X' reacts with chlorine gas to produce a compound $\mathrm{XC}{\mathrm{l}}_3$. $\mathrm{XC}{\mathrm{l}}_3$ is electron deficient and easily reacts with $\mathrm{N}{\mathrm{H}}_3$ to form $\mathrm{C}{\mathrm{l}}_3\mathrm{X}\leftarrow \mathrm{N}{\mathrm{H}}_3$ adduct ; however, $\mathrm{XC}{\mathrm{l}}_3$ does not dimerize X is :

   1. A.B
   2. B.Al
   3. C.Ga
   4. D.In
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   Answer: A

2. Q682018 · 15 Apr 2018 · Shift 1

   For ${\text{Na}}^{+},{\text{Mg}}^{2+},{\text{F}}^{-}$ and ${\text{O}}^{2-}$; the correct order of increasing ionic radii is :

   1. A.${\text{O}}^{2-}<{\text{F}}^{-}<{\text{Na}}^{+}<{\text{Mg}}^{2+}$
   2. B.${\text{Na}}^{+}<{\text{Mg}}^{2+}<{\text{F}}^{-}<{\text{O}}^{2-}$
   3. C.${\text{Mg}}^{2+}<{\text{Na}}^{+}<{\text{F}}^{-}<{\text{O}}^{2-}$
   4. D.${\text{Mg}}^{2+}<{\text{O}}^{2-}<{\text{Na}}^{+}<{\text{F}}^{-}$
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   Answer: C