JEE Main 2021 Question Paper (27-Jul-2021) (Shift 1)

Question 1

Which one of the following compounds will give orange precipitate when treated with $2,4$-dinitrophenyl hydrazine?

Accepted Answer

""

Answer

Answer

Answer

Question 2

The product obtained from the electrolytic oxidation of acidified sulphate solutions is:

Accepted Answer

$\mathrm{HO}_3\mathrm{SOOSO}_3\mathrm{H}$

Answer

$\mathrm{HSO}_{4}^{-}$

Answer

$\mathrm{HO}_2\mathrm{SOSO}_2\mathrm{H}$

Answer

$\mathrm{HO}_3\mathrm{SOSO}_3\mathrm{H}$

Question 3

The parameters of the unit cell of a substance are $ a = 2.5, \quad b = 3.0, \quad c = 4.0, \quad \alpha = 90^\circ, \quad \beta = 120^\circ, \quad \gamma = 90^\circ. $ The crystal system of the substance is :

Accepted Answer

Monoclinic

Answer

Hexagonal

Answer

Orthorhombic

Answer

Triclinic

Question 4

The oxidation states of $'P'$ in ${\mathrm{H}}_{4}{\mathrm{P}}_{2}{\mathrm{O}}_{7}$, ${\mathrm{H}}_{4}{\mathrm{P}}_{2}{\mathrm{O}}_{5}$, and ${\mathrm{H}}_{4}{\mathrm{P}}_{2}{\mathrm{O}}_{6}$, respectively, are:

Accepted Answer

$5, \quad 3$ and $4$

Answer

$7, \quad 5 	ext{ and } 6$

Answer

$5, \quad 4$ and $3$

Answer

$6, \quad 4$ and $5$

Question 5

For a reaction of order $ n $, the unit of the rate constant is :

Accepted Answer

$\mathrm{mol}^{1 - n} \, \mathrm{L}^{n - 1} \, \mathrm{s}^{-1}$

Answer

$\mathrm{mol}^{1-n} \, \mathrm{L}^{1-n} \, \mathrm{s}$

Answer

$\mathrm{mol}^{1-n} \, \mathrm{L}^{2n} \, \mathrm{s}^{-1}$

Answer

$\mathrm{mol}^{1-n} \, \mathrm{L}^{1-n} \, \mathrm{s}^{-1}$