d- and f-Block Elements · JEE Main previous year questions

2016 2 questions

1. Q732016 · 3 Apr 2016 · Shift 1

   The pair having the same magnetic moment is : [At. No.: $\mathrm{Cr}=24,\mathrm{Mn}=25,\mathrm{Fe}=26,\mathrm{Co}=27$]

   1. A.$[\mathrm{Cr}({\mathrm{H}}_2\mathrm{O}{)}_6{]}^{2+}$ and $[\mathrm{Fe}({\mathrm{H}}_2\mathrm{O}{)}_6{]}^{2+}$
   2. B.$[\mathrm{Mn}({\mathrm{H}}_2\mathrm{O}{)}_6{]}^{2+}$ and $[\mathrm{Cr}({\mathrm{H}}_2\mathrm{O}{)}_6{]}^{2+}$
   3. C.$[\mathrm{CoC}{\mathrm{l}}_4{]}^{2-}$ and $[\mathrm{Fe}({\mathrm{H}}_2\mathrm{O}{)}_6{]}^{2+}$
   4. D.$[\mathrm{Cr}({\mathrm{H}}_2\mathrm{O}{)}_6{]}^{2+}$ and $[\mathrm{CoC}{\mathrm{l}}_4{]}^{2-}$
   Show answer

   Answer: A

2. Q862016 · 3 Apr 2016 · Shift 1

   The concentration of fluoride, lead, nitrate and iron in a water sample from an underground lake was found to be 1000 ppb, 40 ppb, 100 ppm and 0.2 ppm, respectively. This water is unsuitable for drinking due to high concentration of :

   1. A.Lead
   2. B.Nitrate
   3. C.Iron
   4. D.Fluoride
   Show answer

   Answer: B