Sample paper · JEE Preparation Chemistry

Chemistry · Sample Paper 3

JEE Main pattern — 20 fresh MCQs and 5 numerical-answer questions on the full Class 11 + 12 Chemistry syllabus, 4 marks each.

25 questions · 100 marks · 60 minutes

Timed, marked on submit · free with an account

General instructions

This paper has 25 questions in two sections. All are compulsory.
Section A — Q1 to Q20: multiple-choice questions with one correct answer.
Section B — Q21 to Q25: numerical-value questions. Type the answer as a number (round to the nearest integer unless stated).
Each correct answer earns 4 marks. In the real JEE Main a wrong answer costs 1 mark; this practice paper does not deduct marks.
Time: 60 minutes — the share of Chemistry in the 3-hour JEE Main paper.

Section A · Multiple choice

Questions 1–20, 4 marks each.

Question 14 marks
The volume of $O_{2}$ at STP needed to burn 4 g of $C H_{4}$ completely is
1. A.5.6 L
2. B.11.2 L
3. C.22.4 L
4. D.44.8 L
Question 24 marks
The wavelength of the second line of the Balmer series of hydrogen corresponds to the transition
1. A.3 → 2
2. B.4 → 2
3. C.5 → 2
4. D.2 → 1
Question 34 marks
The correct order of electron gain enthalpy (most negative first) is
1. A.F > Cl > Br
2. B.Cl > F > Br
3. C.Br > Cl > F
4. D.F > Br > Cl
Question 44 marks
Which molecule has a non-zero dipole moment?
1. A. $B F_{3}$
2. B. $C C l_{4}$
3. C. $N F_{3}$
4. D. $C O_{2}$
Question 54 marks
The magnetic nature and bond order of $O_{2}^{2 -}$ (peroxide) are
1. A.paramagnetic, 1
2. B.diamagnetic, 1
3. C.paramagnetic, 2
4. D.diamagnetic, 2
Question 64 marks
For the reaction $N_{2} (g) + 3 H_{2} (g) \to 2 N H_{3} (g)$ at 300 K, $Δ H - Δ U$ is about
1. A.−4.99 kJ
2. B.+4.99 kJ
3. C.−2.49 kJ
4. D.0
Question 74 marks
The solubility product of $A g C l$ is $1.8 \times 1 0^{- 10}$ . Its solubility in 0.1 M NaCl is
1. A. $1.8 \times 1 0^{- 9}$ M
2. B. $1.34 \times 1 0^{- 5}$ M
3. C. $1.8 \times 1 0^{- 11}$ M
4. D. $1.8 \times 1 0^{- 10}$ M
Question 84 marks
The n-factor of $K M n O_{4}$ in neutral medium (to $M n O_{2}$ ) is
1. A.5
2. B.3
3. C.1
4. D.7
Question 94 marks
The most stable free radical is
1. A. $C H_{3}^{∙}$
2. B. $(C H_{3})_{3} C^{∙}$
3. C. $C H_{3} C H_{2}^{∙}$
4. D. $(C H_{3})_{2} C H^{∙}$
Question 104 marks
Ozonolysis of 2-methylbut-2-ene gives
1. A.acetone and acetaldehyde
2. B.two molecules of acetone
3. C.formaldehyde and acetone
4. D.acetaldehyde only
Question 114 marks
The mole fraction of a solute in a 1 molal aqueous solution is about
1. A.0.018
2. B.0.1
3. C.0.5
4. D.0.0018
Question 124 marks
The charge required to oxidise 1 mol of $F e O$ to $F e_{2} O_{3}$ is
1. A.1 F
2. B.2 F
3. C.3 F
4. D.0.5 F
Question 134 marks
For a first-order reaction, the ratio of times for 75% and 50% completion is
1. A.1
2. B.2
3. C.3
4. D.1.5
Question 144 marks
Which has the highest boiling point?
1. A. $N H_{3}$
2. B. $P H_{3}$
3. C. $A s H_{3}$
4. D. $S b H_{3}$
Question 154 marks
Which ion has the maximum spin-only magnetic moment?
1. A. $F e^{2 +}$
2. B. $M n^{2 +}$
3. C. $C r^{3 +}$
4. D. $C u^{2 +}$
Question 164 marks
The CFSE of a $d^{6}$ low-spin octahedral complex is
1. A. $- 2.4 Δ_{o}$
2. B. $- 0.4 Δ_{o}$
3. C. $- 1.6 Δ_{o}$
4. D.0
Question 174 marks
Which undergoes SN1 reaction fastest?
1. A.benzyl chloride
2. B.chlorobenzene
3. C.ethyl chloride
4. D.methyl chloride
Question 184 marks
Phenol on treatment with $C O_{2}$ and NaOH under pressure, followed by acidification, gives
1. A.salicylaldehyde
2. B.salicylic acid
3. C.benzoic acid
4. D.picric acid
Question 194 marks
Which gives a positive Fehling's test?
1. A.benzaldehyde
2. B.acetone
3. C.ethanal
4. D.acetophenone
Question 204 marks
Which amine reacts with nitrous acid at 273–278 K to give a stable diazonium salt?
1. A.methylamine
2. B.aniline
3. C.dimethylamine
4. D.triethylamine

Section B · Numerical value

Questions 21–25, 4 marks each. Enter a number.

Question 214 marks
Find the molality of a solution containing 9 g of glucose ( $C_{6} H_{12} O_{6}$ , M = 180) in 250 g of water. Give the answer multiplied by 10.
Question 224 marks
How many faradays of charge are needed to deposit 54 g of aluminium from $A l^{3 +}$ ? (Al = 27)
Question 234 marks
Find the number of unpaired electrons in $[C o F_{6}]^{3 -}$ .
Question 244 marks
Find the pH of a 0.005 M solution of $H_{2} S O_{4}$ (assume complete dissociation).
Question 254 marks
How many structural isomers are possible for $C_{5} H_{12}$ ?

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