JEE Main 2021 Question Paper (16-Mar-2021) (Shift 2)

Question 1

The greenhouse gas(es) is (are): (A) Carbon dioxide (B) Oxygen (C) Water vapour (D) Methane Choose the most appropriate answer from the options given below:

Accepted Answer

(A), (C) and (D) only

Answer

(A) and (C) only

Answer

(A) only

Answer

(A) and (B) only

Question 2

In the above reaction, the reagent "$A$" is:

Accepted Answer

Alkaline $\mathrm{KMnO}_4$, $\mathrm{H}^+$

Answer

$ \mathrm{NaBH}_4, \mathrm{H}_3\mathrm{O}^+ $

Answer

$\mathrm{LiAlH}_4$

Answer

$\mathrm{HCl}, \mathrm{Zn}-\mathrm{Hg}$

Question 3

Which of the following reduction reactions CANNOT be carried out with coke?

Accepted Answer

${\mathrm{Al}}_{2}{\mathrm{O}}_{3} 	o \mathrm{Al}$

Answer

$ \mathrm{ZnO} 	o \mathrm{Zn} $

Answer

${\mathrm{Fe}}_{2}{\mathrm{O}}_{3} 	o \mathrm{Fe}$

Answer

$\mathrm{Cu}_2\mathrm{O} 	o \mathrm{Cu}$

Question 4

Identify the elements $ \mathrm{X} $ and $ \mathrm{Y} $ using the ionization energy values given below: $ \begin{array}{ccc} & \text{Ionization energy} & (\mathrm{kJ}/\mathrm{mol}) \ & 1^{\mathrm{st}} & 2^{\mathrm{nd}} \ \mathrm{X} & 495 & 4563 \ \mathrm{Y} & 731 & 1450 \ \end{array} $

Accepted Answer

$ \mathrm{X} = \mathrm{Na}; \quad \mathrm{Y} = \mathrm{Mg} $

Answer

$ \mathrm{X} = \mathrm{Mg}; \quad \mathrm{Y} = \mathrm{F} $

Answer

$ \mathrm{X} = \mathrm{Mg}; \quad \mathrm{Y} = \mathrm{Na} $

Answer

$ \mathrm{X} = \mathrm{F}; \quad \mathrm{Y} = \mathrm{Mg} $

Question 5

Identify the reagent(s) $\mathrm{A}$ and condition(s) for the reaction :

Accepted Answer

$ \mathrm{A} = \mathrm{Cl}_2$; $\mathrm{UV}$ light

Answer

$ \mathrm{A} = \mathrm{HCl} $; Anhydrous $ \mathrm{AlCl}_3 $

Answer

$ \mathrm{A} = \mathrm{HCl}, \mathrm{ZnCl}_2 $

Answer

$ \mathrm{A} = \mathrm{Cl}_2$; dark, anhydrous $ \mathrm{AlCl}_3$