Other Chemistry · JEE Main previous year questions

650 questions asked across 20 exam years, newest first

Year-wise papers Topic-wise questions

Practise this topic

2021 58 questions

Q652021 · 25 Jul 2021 · Shift 2
$C_{6} H_{5} N O_{2} Sn + HCl$ "A" $C_{6} H_{5} N \oplus_{2} Cl ⊖ H^{\oplus}$ P (Yellow coloured Compound) Consider the above reaction, the product "P" is :
1. A.[structure: $C_{6} H_{5} - N = N - C_{6} H_{4} - N H_{2}$ with $N H_{2}$ ortho to the azo group]
2. B.[structure: $C_{6} H_{5} - N = N - C_{6} H_{4} - N H_{2}$ with $N H_{2}$ para to the azo group]
3. C.[structure: $C_{6} H_{5} - NH - C_{6} H_{5}$ ]
4. D.[structure: $C_{6} H_{5} - N = N - NH - C_{6} H_{5}$ ]
Show answer
Answer: B
Q682021 · 25 Jul 2021 · Shift 2
1. A.
2. B.
3. C.
4. D.
Show answer
Answer: C
Q692021 · 25 Jul 2021 · Shift 2
Identify the species having one $π$ -bond and maximum number of canonical forms from the following :
1. A. $S O_{3}$
2. B. $O_{2}$
3. C. $S O_{2}$
4. D. $C O_{3}^{2 -}$
Show answer
Answer: D
Q752021 · 25 Jul 2021 · Shift 2
Which among the following is the strongest acid ?
1. A. $C H_{3} C H_{2} C H_{2} C H_{3}$
2. B.[structure: toluene]
3. C.[structure: cyclopropene]
4. D.[structure: cyclopenta-1,3-diene]
Show answer
Answer: D
Q772021 · 25 Jul 2021 · Shift 2
Match List I with List II : $(a) (b) (c) (d) List-I Elements Li Na K Cs (i) (ii) (iii) (iv) List-II Properties Poor water solubility of I^{-} salt Most abundant element in cell fluid Bicarbonate salt used in fire extinguisher Carbonate salt decomposes easily on heating$ Choose the correct answer from the options given below :
1. A.(a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)
2. B.(a)-(i), (b)-(iii), (c)-(ii), (d)-(iv)
3. C.(a)-(iv), (b)-(ii), (c)-(iii), (d)-(i)
4. D.(a)-(i), (b)-(ii), (c)-(iii), (d)-(iv)
Show answer
Answer: A
Q862021 · 25 Jul 2021 · Shift 2· Numerical answer
Assuming that $Ba (OH)_{2}$ is completely ionised in aqueous solution under the given conditions the concentration of $H_{3} O^{+}$ ions in 0.005 M aqueous solution of $Ba (OH)_{2}$ at 298 K is ____ $\times 1 0^{- 12} mol L^{- 1}$ . (Nearest integer)
Show answer
Answer: 1
Q892021 · 25 Jul 2021 · Shift 2· Numerical answer
The number of significant figures in 0.00340 is ____________.
Show answer
Answer: 3
Q612021 · 22 Jul 2021 · Shift 2
Which one of the following statements for D.I. Mendeleeff, is incorrect?
1. A.He authored the textbook - Principles of Chemistry
2. B.At the time, he proposed Periodic Table of elements structure of atom was known.
3. C.Element with atomic number 101 is named after him.
4. D.He invented accurate barometer.
Show answer
Answer: B
Q632021 · 20 Jul 2021 · Shift 1
The correct order of intensity of colors of the compounds is :
1. A. $[Ni (CN)_{4}]^{2 -} > [NiCl_{4}]^{2 -} > [Ni (H_{2} O)_{6}]^{2 +}$
2. B. $[Ni (H_{2} O)_{6}]^{2 +} > [NiCl_{4}]^{2 -} > [Ni (CN)_{4}]^{2 -}$
3. C. $[NiCl_{4}]^{2 -} > [Ni (H_{2} O)_{6}]^{2 +} > [Ni (CN)_{4}]^{2 -}$
4. D. $[NiCl_{4}]^{2 -} > [Ni (CN)_{4}]^{2 -} > [Ni (H_{2} O)_{6}]^{2 +}$
Show answer
Answer: C
Q682021 · 20 Jul 2021 · Shift 1
Compound A is converted to B on reaction with $CHCl_{3}$ and $KOH$ . The compound B is toxic and can be decomposed by C. A, B and C respectively are :
1. A.primary amine, nitrile compound, conc. $HCl$
2. B.secondary amine, isonitrile compound, conc. $NaOH$
3. C.primary amine, isonitrile compound, conc. $HCl$
4. D.secondary amine, nitrile compound, conc. $NaOH$
Show answer
Answer: C
Q692021 · 20 Jul 2021 · Shift 1
Identify the incorrect statement from the following
1. A.Amylose is a branched chain polymer of glucose
2. B.Starch is a polymer of $α$ -D glucose
3. C. $β$ -Glycosidic linkage makes cellulose polymer
4. D.Glycogen is called as animal starch
Show answer
Answer: A
Q732021 · 20 Jul 2021 · Shift 1
The set in which compounds have different nature is :
1. A. $B(OH)_{3}$ and $H_{3} PO_{3}$
2. B. $B(OH)_{3}$ and $Al(OH)_{3}$
3. C. $NaOH$ and $Ca(OH)_{2}$
4. D. $Be(OH)_{2}$ and $Al(OH)_{3}$
Show answer
Answer: B
Q742021 · 20 Jul 2021 · Shift 1
Given below are two statements. One is labelled as Assertion A and the other is labelled as Reason R. Assertion A : Sharp glass edge becomes smooth on heating it upto its melting point. Reason R : The viscosity of glass decreases on melting. Choose the most appropriate answer from the options given below.
1. A.A is true but R is false
2. B.Both A and R are true but R is NOT the correct explanation of A.
3. C.A is false but R is true.
4. D.Both A and R are true and R is the correct explanation of A.
Show answer
Answer: B
Q752021 · 20 Jul 2021 · Shift 1
Orlon fibres are made up of :
1. A.Polyacrylonitrile
2. B.Polyesters
3. C.Polyamide
4. D.Cellulose
Show answer
Answer: A
Q762021 · 20 Jul 2021 · Shift 1
Given below are two statements : One is labelled as Assertion A and other is labelled as Reason R. Assertion A : The dihedral angles in $H_{2} O_{2}$ in gaseous phase is $90. 2^{\circ}$ and in solid phase is $111. 5^{\circ}$ . Reason R : The change in dihedral angle in solid and gaseous phase is due to the difference in the intermolecular forces. Choose the most appropriate answer from the options given below for A and R.
1. A.A is correct but R is not correct.
2. B.Both A and R are correct but R is not the correct explanation of A.
3. C.Both A and R are correct and R is the correct explanation of A.
4. D.A is not correct but R is correct.
Show answer
Answer: D
Q822021 · 20 Jul 2021 · Shift 1· Numerical answer
$250 mL$ of $0.5 M$ $NaOH$ was added to $500 mL$ of $1 M$ $HCl$ . The number of unreacted $HCl$ molecules in the solution after complete reaction is ________ $\times 1 0^{21}$ . (Nearest integer) ( $N_{A} = 6.022 \times 1 0^{23}$ )
Show answer
Answer: 226
Q652021 · 18 Mar 2021 · Shift 1
A non-reducing sugar "A" hydrolyses to give two reducing mono saccharides. Sugar A is
1. A.Fructose
2. B.Galactose
3. C.Glucose
4. D.Sucrose
Show answer
Answer: D
Q852021 · 18 Mar 2021 · Shift 1· Numerical answer
____ grams of 3-Hydroxy propanal (MW = 74) must be dehydrated to produce 7.8 g of acrolein (MW = 56) ( $C_{3} H_{4} O$ ) if the percentage yield is 64. (Round off to the Nearest Integer). [Given : Atomic masses : C : 12.0 u, H : 1.0 u, O : 16.0 u ]
Show answer
Answer: 16
Q902021 · 18 Mar 2021 · Shift 1· Numerical answer
Complete combustion of 3g of ethane gives $x \times 1 0^{22}$ molecules of water. The value of x is ____. (Round off to the Nearest Integer). [Use : $N_{A} = 6.023 \times 1 0^{23}$ ; Atomic masses in u : C : 12.0; O : 16.0; H : 1.0]
Show answer
Answer: 18
Q652021 · 18 Mar 2021 · Shift 2
The oxide that shows magnetic property is :
1. A. $MgO$
2. B. $Si O_{2}$
3. C. $M n_{3} O_{4}$
4. D. $N a_{2} O$
Show answer
Answer: C
Q722021 · 18 Mar 2021 · Shift 2
1. A.
2. B.
3. C.
4. D.
Show answer
Answer: D
Q732021 · 18 Mar 2021 · Shift 2
1. A.
2. B.
3. C.
4. D.
Show answer
Answer: A
Q762021 · 18 Mar 2021 · Shift 2
A hard substance melts at high temperature and is an insulator in both solid and in molten state. This solid is most likely to be a/an :
1. A.Covalent solid
2. B.Molecular solid
3. C.Ionic solid
4. D.Metallic solid
Show answer
Answer: A
Q822021 · 18 Mar 2021 · Shift 2· Numerical answer
$10.0 mL$ of $N a_{2} C O_{3}$ 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 $N a_{2} C O_{3}$ solution is ____ $mM$ . (Round off to the Nearest Integer).
Show answer
Answer: 50
Q882021 · 18 Mar 2021 · Shift 2· Numerical answer
The solubility of $CdS O_{4}$ in water is $8.0 \times 1 0^{- 4} mol L^{- 1}$ . Its solubility in $0.01 M$ $H_{2} S O_{4}$ solution is ____ $\times 1 0^{- 6} mol L^{- 1}$ . (Round off to the Nearest Integer). (Assume that solubility is much less than $0.01 M$ )
Show answer
Answer: 64