JEE Main 2021 Question Paper (20-Jul-2021) (Shift 1)

Question 1

According to the valence bond theory, the hybridization of the central metal atom is ${\mathrm{dsp}}^{2}$ for which one of the following compounds?

Accepted Answer

$\mathrm{K}_{2}\left[\mathrm{Ni}(\mathrm{CN})_{4}\right]$

Answer

$\mathrm{NiCl}_2 \cdot 6\mathrm{H}_2\mathrm{O}$

Answer

$\left[\mathrm{Ni}(\mathrm{CO})_{4}\right]$

Answer

$ \mathrm{Na}_2[\mathrm{NiCl}_4] $

Question 2

The correct structure of Ruhemann's Purple, the compound formed in the reaction of Ninhydrin with proteins is:

Accepted Answer

""

Answer

Answer

Answer

Question 3

Green chemistry in day-to-day life is in the use of:

Accepted Answer

Liquified ${\mathrm{CO}}_{2}$ for dry cleaning of clothes

Answer

Chlorine for bleaching of paper

Answer

Large amount of water alone for washing clothes

Answer

Tetrachloroethene for laundry

Question 4

The correct order of intensity of colors of the compounds is:

Accepted Answer

${\left[\mathrm{NiCl}_4\right]}^{2-} > {\left[\mathrm{Ni}\left(\mathrm{H}_2\mathrm{O}\right)_6\right]}^{2+} > {\left[\mathrm{Ni}(\mathrm{CN})_4\right]}^{2-}$

Answer

${\left[\mathrm{Ni}(\mathrm{CN})_{4}\right]}^{2-} > {\left[\mathrm{NiCl}_{4}\right]}^{2-} > {\left[\mathrm{Ni}(\mathrm{H}_{2}\mathrm{O})_{6}\right]}^{2+}$

Answer

$\left[\mathrm{Ni}\left(\mathrm{H}_{2}\mathrm{O}\right)_{6}\right]^{2+} > \left[\mathrm{NiCl}_{4}\right]^{2-} > \left[\mathrm{Ni}(\mathrm{CN})_{4}\right]^{2-}$

Answer

${\left[\mathrm{NiCl}_4\right]}^{2-} > {\left[\mathrm{Ni}(\mathrm{CN})_4\right]}^{2-} > {\left[\mathrm{Ni}(\mathrm{H}_2\mathrm{O})_6\right]}^{2+}$

Question 5

The set in which compounds have different nature is:

Accepted Answer

$ \mathrm{B}(\mathrm{OH})_{3}$ and $ \mathrm{Al}(\mathrm{OH})_{3}$

Answer

$ \mathrm{B}(\mathrm{OH})_{3} $ and $ \mathrm{H}_{3}\mathrm{PO}_{3} $

Answer

$ \mathrm{NaOH}$ and $ \mathrm{Ca}(\mathrm{OH})_{2}$

Answer

$ \mathrm{Be}(\mathrm{OH})_{2}$ and $ \mathrm{Al}(\mathrm{OH})_{3}$