JEE MAIN - Chemistry (2021 - 18th March Evening Shift)

1
Deficiency of vitamin K causes :
Answer
(C)
Increase in blood clotting time
2
In the following molecule,

JEE Main 2021 (Online) 18th March Evening Shift Chemistry - Basics of Organic Chemistry Question 151 English
Hybridisation of Carbon a, b, and c respectively are :
Answer
(A)
sp3, sp2, sp2
3
JEE Main 2021 (Online) 18th March Evening Shift Chemistry - Compounds Containing Nitrogen Question 133 English
Consider the given reaction, percentage yield of :
Answer
(D)
C > B > A
4
Given below are two statements :

Statement I : C2H5OH and AgCN both can generate nucleophile.

Statement II : KCN and AgCN both will generate nitrile nucleophile with all reaction conditions.

Choose the most appropriate option :
Answer
(D)
Statement I is true but statement II is false.
5
The oxide that shows magnetic property is :
Answer
(C)
Mn3O4
6
In the reaction of hypobromite with amide, the carbonyl carbon is lost as :
Answer
(D)
CO$$_3^{2 - }$$
7
The secondary valency and the number of hydrogen bonded water molecule(s) in CuSO4 . 5H2O, respectively, are :
Answer
(B)
4 and 1
8
The first ionization energy of magnesium is smaller as compared to that of elements X and Y, but higher than that of Z. The elements X, Y and Z, respectively, are :
Answer
(B)
argon, chlorine and sodium
9
Given below are two statements :

Statement I : Bohr's theory accounts for the stability and line spectrum of Li+ ion.

Statement II : Bohr's theory was unable to explain the splitting of spectral lines in the presence of a magnetic field.

In the light of the above statements, choose the most appropriate answer from the options given below :
Answer
(A)
Statement I is false but statement II is true.
10
The oxidation states of nitrogen in NO, NO2, N2O and NO$$_3^ - $$ are in the order of :
Answer
(D)
NO$$_3^ - $$ > NO2 > NO > N2O
11
An organic compound "A" on treatment with benzene sulphonyl chloride gives compound B. B is soluble in dil. NaOH solution. Compound A is :
Answer
(A)
JEE Main 2021 (Online) 18th March Evening Shift Chemistry - Compounds Containing Nitrogen Question 134 English Option 1
12
Main products formed during a reaction of 1-methoxy naphthalene with hydroiodic acid are :
Answer
(D)
JEE Main 2021 (Online) 18th March Evening Shift Chemistry - Haloalkanes and Haloarenes Question 85 English Option 4
13
JEE Main 2021 (Online) 18th March Evening Shift Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 127 English
Consider the above reaction, the product 'X' and 'Y' respectively are :
Answer
(A)
JEE Main 2021 (Online) 18th March Evening Shift Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 127 English Option 1
14
In Tollen's test for aldehyde, the overall number of electron(s) transferred to the Tollen's reagent formula [Ag(NH3)2]+ per aldehyde group to form silver mirror is ___________. (Round off to the Nearest Integer).
Answer
2
15
10.0 mL of Na2CO3 solution is titrated against 0.2 M HCl solution. The following titre values were obtained in 5 readings :

4.8 mL, 4.9 mL, 5.0 mL, 5.0 mL and 5.0 mL

Based on these readings, and convention of titrimetric estimation the concentration of Na2CO3 solution is ___________ mM.

(Round off to the Nearest Integer).
Answer
50
16
The number of species below that have two lone pairs of electrons in their central atom is _________. (Round off to the Nearest Integer).

SF4, BF$$_4^ - $$, ClF3, AsF3, PCl5, BrF5, XeF4, SF6
Answer
2
17
JEE Main 2021 (Online) 18th March Evening Shift Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 126 English
Consider the above reaction where 6.1 g of Benzoic acid is used to get 7.8 g of m-bromo benzoic acid. The percentage yield of the product is __________

(Round off to the Nearest Integer).

[Given : Atomic masses : C : 12.0 u, H : 1.0 u, O : 16.0 u, Br : 80.0 u]
Answer
78
18
The molar conductivities at infinite dilution of barium chloride, sulphuric acid and hydrochloric acid are 280, 860 and 426 S cm2 mol$$-$$1 respectively. The molar conductivity at infinite dilution of barium sulphate is _________ S cm2 mol$$-$$1. (Round off to the Nearest Integer ).
Answer
288
19
The gas phase reaction $$2A(g) \rightleftharpoons {A_2}(g)$$ at 400 K has $$\Delta$$Go = + 25.2 kJ mol-1.

The equilibrium constant KC for this reaction is ________ $$\times$$ 10$$-$$2. (Round off to the Nearest Integer).

[Use : R = 8.3 J mol$$-$$1 K$$-$$1, ln 10 = 2.3 log10 2 = 0.30, 1 atm = 1 bar]

[antilog ($$-$$0.3) = 0.501]
Answer
2
20
A reaction has a half life of 1 min. The time required for 99.9% completion of the reaction is _________ min. (Round off to the Nearest Integer). [Use : ln 2 = 0.69; ln 10 = 2.3]
Answer
10
21
The solubility of CdSO4 in water is 8.0 $$\times$$ 10$$-$$4 mol L$$-$$1. Its solubility in 0.01 M H2SO4 solution is __________ $$\times$$ 10$$-$$6 mol L$$-$$1. (Round off to the Nearest Integer). (Assume that solubility is much less than 0.01 M)
Answer
64
22
A solute A dimerizes in water. The boiling point of a 2 molal solution of A is 100.52$$^\circ$$C. The percentage association of A is __________. (Round off to the Nearest Integer).

[Use : Kb for water = 0.52 K kg mol$$-$$1 Boiling point of water = 100$$^\circ$$C]
Answer
100