All Courses
Get the App Signup / Login
Sign in Open App
All Exams  >   JEE  >   Mock Tests for JEE Main and Advanced 2025  >   All Questions

All questions of Chemistry for JEE Exam

Clear all your JEE doubts with EduRev

The number of atoms of hydrogen in 2 moles of NH3
  • a)
    5 * 1023
  • b)
    3.01 * 1023
  • c)
    3.61 * 1024
  • d)
    4.8 * 1024
Correct answer is option 'C'. Can you explain this answer?

Geetika Shah answered
Therefore 2 moles will have 1.204*1024 molecules of NH3.
There are 3 atoms in each molecule, so 2 moles will have 3*(1.204*1024) atoms
which is 3.61 * 1024 atoms.

Out of the two compounds shown below, the vapour 
pressing of B at a particular temperature is expected 
to be
  • a)
    higher than that of A
  • b)
    lower than that of A
  • c)
    Same as that of A
  • d)
    can be higher or lower depending upon the size
Correct answer is option 'A'. Can you explain this answer?

Amisha answered
A has inter H bonding ...while B has intra H bonding....due to inter H bonding in A ,less vapours of A will be formed as compared to B .... and hence more vapours of B will be formed and hence it will have higher vapour pressure....

Calculated bond order in the superoxide () ion is 
  • a)
    2.5
  • b)
    2
  • c)
    1.5
  • d)
    1
Correct answer is option 'C'. Can you explain this answer?

Aditi Azade answered
O2^- (superoxide) = 13 valence e⁻. = σs(2 e⁻) σs*(2e⁻) σp(2e⁻) πp(4e⁻) πp*(3e⁻) σp*(0) . bond order = ½[ σs(2e⁻) σp(2e⁻) πp(4 e⁻) - σs*(2e⁻) πp*(3e⁻) ]. = ½[8-5] = 1.5

Can you explain the answer of this question below:

Vapour density of a metal chloride is 66. Its oxide contains 53% metal. The atomic weight of the metal is

  • A:

    21

  • B:

    54

  • C:

    27.06 

  • D:

    2.086

The answer is c.

Rahul Bansal answered
Equivalent of metal = Equivalent of chloride

53/n = 47/8 , E = 9.02 , Atomic mass of metal = n X 9.02

Molecular mass of chloride = 2 X 66 = n X 9.02 + n X 35.5

on solving n = 3

Atomic mass of metal = 9.02 X 3 = 27.06

IUPAC name of compound  is
  • a)
    4-methyl-3-hexanol
  • b)
    heptanol
  • c)
    4-methyl-2-hexanol
  • d)
    none of these
Correct answer is option 'C'. Can you explain this answer?

Gagan Chandu answered
The functional group is OH and it should get low locant and longest chain should be selected for naming so methane becomes substituient and get locant number 4

Alcohol can be obtained by all methods except
  • a)
  • b)
    HCL
  • c)
  • d)
Correct answer is option 'C'. Can you explain this answer?

Ashish Tiwary answered
Bcz water
 or alcohols would protonate and thus 
destroy the Grignard reagent
, because the 
Grignard
 carbon is highly nucleophilic.

The correct increasing bond angle among ,  and 
  • a)
  • b)
  • c)
  • d)
Correct answer is option 'C'. Can you explain this answer?

Sushmita Singh answered
In case of BF3 back bonding is possible whereas in Pf3 and Clf3 the bond angle is based on the electronegativity difference. hence BF3 has the highest bond angle. it can also be explained by taking out the hybridisation of the following compounds the hybridisation of BF3 is SP2, the hybridisation of Pf3 is SP3 and the hybridization of Clf3 is sp3d .As BF3 has SP2 hybridization so it has the maximum bond angle

How many different dichlorides, including stereoisomers by Wurtz coupling reaction with ethereal solution of sodium, can give 1,4-dimethyl cyclohexane ?
  • b)

     
Correct answer is '7'. Can you explain this answer?

Tanuja Kapoor answered
In 1-4-dimethyl cyclohexane, the following indicated bonds can be formed in the given reaction condition

Therefore following dichlorides can be used for this purpose

(I) has two chiral carbons, hence it has four stereoisomers.

(II) Also has two chiral carbons but there are only three stereoismers as one of them is meso.

 20 g of an ideal gas contains only atoms of S and O occupies 5.6 L at NPT. What is the mol. wt. of gas ?
  • a)
    64
  • b)
    80
  • c)
    96
  • d)
    None of these
Correct answer is option 'B'. Can you explain this answer?

Ruchi Tiwari answered
Given,
Mass of gas = 20 g
Pressure of gas = 1 atm
Volume of gas = 5.6 L
Temperature of gas = 273 K
Using ideal gas law,

where,
P = pressure of the gas
V = volume of the gas
T = temperature of the gas
n = number of moles of the gas
R = gas constant = 0.0821
Latm/moleK
M = molar mass of gas
w = mass of gas
Now put all the given values in the formula, we get
Therefore, the molar mass of the gas is, 80.0475 g/mole

The uncertainty found from the uncertainty principle  is
  • a)
    the minimum value
  • b)
    the maximum value
  • c)
    the exact value
  • d)
    only an approximate value
Correct answer is option 'A'. Can you explain this answer?

Rishu Singh answered
Heisenberg uncertainty principle states that exact momentum and exact position of matter wave can't be determined simultaneously.
∆P.∆X>equal to h/4π

How many elements have more ionisation energy as compared to their next higher atomic number element?
Na, Mg, Al, Si, P, S, Cl, Ar
    Correct answer is '3'. Can you explain this answer?

    Janhavi Mukherjee answered
    Explanation:

    Ionisation energy is the energy required to remove an electron from a gaseous atom or ion. It increases as we move from left to right across a period of the periodic table, i.e., as the atomic number increases. Therefore, the ionisation energy of an element is generally higher than its next higher atomic number element. However, there are some exceptions to this trend, which can be explained by the electronic configuration of the elements.


    Analysis of each element:


    • Na: Sodium has one electron in its outermost shell, which is easier to remove than the electrons in the inner shells. Therefore, its ionisation energy is lower than its next higher atomic number element (Mg).

    • Mg: Magnesium has two electrons in its outermost shell, which are more difficult to remove than the single electron in the outer shell of sodium. Therefore, its ionisation energy is higher than its next higher atomic number element (Al).

    • Al: Aluminum has three electrons in its outermost shell, which are easier to remove than the electrons in the inner shells. Therefore, its ionisation energy is lower than its next higher atomic number element (Si).

    • Si: Silicon has four electrons in its outermost shell, which are more difficult to remove than the three electrons in the outer shell of aluminum. Therefore, its ionisation energy is higher than its next higher atomic number element (P).

    • P: Phosphorus has five electrons in its outermost shell, which are easier to remove than the electrons in the inner shells. Therefore, its ionisation energy is lower than its next higher atomic number element (S).

    • S: Sulfur has six electrons in its outermost shell, which are more difficult to remove than the five electrons in the outer shell of phosphorus. Therefore, its ionisation energy is higher than its next higher atomic number element (Cl).

    • Cl: Chlorine has seven electrons in its outermost shell, which are easier to remove than the electrons in the inner shells. Therefore, its ionisation energy is lower than its next higher atomic number element (Ar).

    • Ar: Argon has eight electrons in its outermost shell, which are more difficult to remove than the seven electrons in the outer shell of chlorine. Therefore, its ionisation energy is higher than its next higher atomic number element (none).



    Conclusion:

    Out of the given elements, there are only three elements (Mg, Si, and Ar) that have more ionisation energy as compared to their next higher atomic number element. The electronic configuration of these elements explains their higher ionisation energy as compared to their next higher atomic number element.

    The spectrum of He is expected to be similar to that of
    • a)
      H
    • b)
    • c)
      Na
    • d)
    Correct answer is option 'B'. Can you explain this answer?

    Sarita Yadav answered
    The spectrum of an atom depends on the number of electrons present in it. Here, helium has two electrons, so the spectrum of Li+ (Z = 3) is similar to that of helium because both He and Li+ have two electrons.

    A metal crystallizes with a face-centered cubic lattice. The edge of the unit cell is 408 pm. The diameter of the metal atom is
    • a)
      144 pm
    • b)
      204 pm
    • c)
      288 pm
    • d)
      408 pm
    Correct answer is option 'C'. Can you explain this answer?

    Naina Bansal answered
    For an FCC cubic lattice:
    r=a√2/4
    where,
    r is the radius of atom
    a is the edge length of unit cell   
    r=408x1.414/4 
    =144.228 pm
    Therefore, diameter of metal atom = 2 x 144.228 pm = 288.456 pm

    To which class of compounds do enzymes usually belong ?
    • a)
      Carbohydrate
    • b)
      Protein
    • c)
      Lipid
    • d)
      Nucleic acid
    Correct answer is 'B'. Can you explain this answer?

    Shilpa Desai answered
    Enzymes belong to the class of compounds known as proteins.
    Enzymes are large protein molecules that act as biological catalysts, speeding up chemical reactions within living organisms. They are made up of long chains of amino acids that are folded into complex 3D structures. Proteins are one of the four major classes of biological macromolecules, along with carbohydrates, lipids, and nucleic acids.

    Key Points:
    - Enzymes are specialized proteins that catalyze specific reactions in biological systems.
    - Proteins are composed of long chains of amino acids linked together by peptide bonds.
    - The unique sequence of amino acids in a protein determines its specific structure and function.
    - Enzymes play a crucial role in metabolism, signaling, and other cellular processes.
    - Each enzyme is specific to a particular substrate, and the active site of the enzyme binds to the substrate to facilitate the chemical reaction.
    - Enzymes can be denatured or inhibited by changes in pH, temperature, or the presence of specific inhibitors.

    Which of the following alkenes will react fastest 
    with 
     under catalytic hydrogenation conditions
    • a)
    • b)
    • c)
    • d)
    Correct answer is option 'A'. Can you explain this answer?

    Learners Habitat answered
    • Catalytic hydrogenation involves the addition of hydrogen (H2) across the double bonds in alkenes, facilitated by a catalyst such as palladium, platinum, or nickel.
    • The rate of hydrogenation is influenced by the stability of the alkene. Less substituted alkenes (fewer alkyl groups attached) react faster because they are less stable.
    • Alkene A, being less substituted compared to the others, will react the fastest under catalytic hydrogenation conditions because it is less stable and thus more reactive.

    The enthalpy of fusion of water is 1.435 kcal/mol. The molar entropy change for the melting of ice at 0°C is
    • a)
      5.260 cal/(mol K)
    • b)
      0.526 cal/(mol K)
    • c)
      10.52 cal/(mol K)
    • d)
      21.04 cal/(mol K)
    Correct answer is option 'A'. Can you explain this answer?

    EduRev JEE answered
    • To find the molar entropy change (ΔS) during the melting of ice, use the formula:
    • ΔS = ΔH/T
    • Where:
      • ΔH is the enthalpy of fusion = 1.435 kcal/mol = 1435 cal/mol (since 1 kcal = 1000 cal)
      • T is the temperature in Kelvin = 0°C = 273.15 K
    • Now, calculate ΔS:
    • ΔS = 1435 cal/mol / 273.15 K ≈ 5.26 cal/(mol K)
    • Thus, the correct answer is option A: 5.260 cal/(mol K).

    In the presence of platinum catalyst, hydrocarbon A 
    adds hydrogen to form n-hexane. When hydrogen 
    bromide is added to A instead of hydrogen, only a 
    single bromo compound is formed. Which of the 
    following is A ?
    • a)
    • b)
    • c)
    • d)
    Correct answer is option 'A'. Can you explain this answer?

    Leelu Bhai answered
    With rkxn with H₂/Pd, each will give n-hexane but when it is reacted with HBr then according to markonikov rule the Br⁻ ion will attach to that carbon consisting of lower H atoms.
    also the ques is asking that there will be single bromo compound is formed.

    now see, in option A, the Br– ion can attack on either 3rd or 4th carbon atom bcz there are same no. of H atoms, and hence a single bromo is formed i.e, 3-bromohexane...
    and if HBr attacks on any other compounds given in options then there can be two products formed, one major and one minor.

    so, option A is correct...
    i hope u will understand

    Conectrated HCl contains
    • a)
      38% HCl by weight (approximately 12 M)
    • b)
      98% HCl by weight (approximately 36 N)
    • c)
      65% HCl by weight (approximately 18 N)
    • d)
      20% HCl by weight (approximately 8 N)
    Correct answer is option 'A'. Can you explain this answer?

    Adi..🤪🐥🔐 answered
    Option a is correct .
    density of solution = 1.19 glml 

    Molarity = MolarmassofHCl1.19​×1000×38%

    =36.51.19​×1000×10038​

    12.389m

    mole of HCl required to make 10 L of all 0.1MHCl=10×0.1=1mole

    12.389×v=1

    v=12.3891​=80.7ml

    The correct representation of Charle’s law is given 
    by
    • a)
    • b)
    • c)
    • d)
    Correct answer is option 'C'. Can you explain this answer?

    Bhawana Pant answered
    Volume is directly proportional to Temperature as temperature increase volume also increase and the graph of v and t starts from 0degree celcius or from -273.5 Kelvin which gives a straight line slope

    Reactivity of hydrogen atoms attached to different 
    carbon atoms in alkanes has the order
    • a)
      Tertiary > Primary > Secondary
    • b)
      Primary > Secondary > Tertiary
    • c)
      Both 1 and 2
    • d)
      Tertiary > Secondary > Primary
    Correct answer is option 'D'. Can you explain this answer?

    EduRev JEE answered
    The reactivity of hydrogen atoms in alkanes varies based on the type of carbon atom they are attached to.
    • Tertiary hydrogen atoms are most reactive.
    • Next in reactivity are Secondary hydrogen atoms.
    • Primary hydrogen atoms are the least reactive.
    This order of reactivity is due to the stability of the resulting radicals formed when the hydrogen is removed. Tertiary radicals are the most stable, followed by secondary, and then primary.

    Which of the following aldehydes forms a stable 
    hydrate ? 
    • a)
      Formaldehyde 
    • b)
      Acetaldehyde 
    • c)
      Trichlorocetaldehyde 
    • d)
      Propionaldehyde
    Correct answer is option 'C'. Can you explain this answer?

    Mira Sharma answered
    Chloral hydrate is stable not so much because the geminal diol is stabilized, but because the aldehyde form is destabilized as compared to, say, acetaldehyde (which also hydrates reversibly in acidic aqueous solution). The sp2 hybridized carbon in the aldehyde is very electron deficient, so it reacts with electron-rich nucleophiles (like water). Acetaldehyde, with a methyl group, slightly reduces the electron deficiency by "donating" some electron density. Trichloroacetaldehyde, however, cannot donate nearly as much electron density because the electronegative chlorine atoms are pulling electron density away from the already electron-deficient carbon, making it even more reactive.
    Formaldehyde, like trichloroacetaldehyde, exists primarily as the diol form, and even oligomerizes and polymerizes  with itself in the absence of water (1,3,5 trioxane and "paraformaldehyde"). Here the issue is not electronegativity (the hydrogen substituents are fairly electron-rich, and energetically favorable to share). Unfortunately, there is a symmetry mismatch in the orbitals involved, so it is impossible for the hydrogen substituents to ease the sp2 carbon's deficiency. Therefore, formaldehyde reacts with water, alcohols, proteins, even itself, to relieve the strain.

    Heating methyl phenyl ether with HI gives 
    • a)
      Methanol Iodobenzene 
    • b)
      Methyl iodide Iodobenzene 
    • c)
      Methyl alcohol Benzyl alcohol 
    • d)
      Methyl iodide Phenol
    Correct answer is option 'D'. Can you explain this answer?

    Raj Jain answered
    Heating methyl phenyl ether with HI gives
    Explanation:
    When methyl phenyl ether (also known as anisole) is heated with HI (hydrogen iodide), a substitution reaction takes place. In this reaction, the hydrogen atom of the methyl group in methyl phenyl ether is replaced by an iodine atom from HI. The reaction can be represented as follows:

    Methyl phenyl ether + HI → Methyl iodide + Phenol

    Details:

    Step 1: Formation of a carbocation intermediate
    - The first step of the reaction involves the protonation of the ether oxygen by the hydrogen iodide (HI) to form an oxonium ion intermediate.
    - The oxonium ion then undergoes heterolysis, breaking the bond between the carbon and oxygen atoms, resulting in the formation of a carbocation intermediate.
    - The carbocation intermediate is stabilized by resonance with the phenyl group.

    Step 2: Nucleophilic substitution
    - In the second step, the iodide ion (I-) acts as a nucleophile and attacks the positively charged carbocation.
    - The nucleophilic attack leads to the formation of a new carbon-iodine bond, while the oxygen atom receives a lone pair of electrons.
    - The resulting products are methyl iodide and phenol.

    Conclusion:
    The correct answer is option D, which states that heating methyl phenyl ether with HI gives methyl iodide and phenol as products.

    With respect to chlorine, hydrogen will be
    • a)
      Electropositive
    • b)
      Electronegative
    • c)
      Neutral
    • d)
      None of these
    Correct answer is option 'A'. Can you explain this answer?

    Anjana Sharma answered
    With respect to Chlorine, hydrogen will be electropositive.

    Reason:

    Chlorine being a strong electronegative element tends to force hydrogen to lose electron and hydrogen acquire electropositive character so that chlorine can complete its octet. 

    Chapter doubts & questions for Chemistry - Mock Tests for JEE Main and Advanced 2025 2025 is part of JEE exam preparation. The chapters have been prepared according to the JEE exam syllabus. The Chapter doubts & questions, notes, tests & MCQs are made for JEE 2025 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests here.

    Chapter doubts & questions of Chemistry - Mock Tests for JEE Main and Advanced 2025 in English & Hindi are available as part of JEE exam. Download more important topics, notes, lectures and mock test series for JEE Exam by signing up for free.

    Related JEE Content

    Signup to see your scores go up within 7 days!

    Study with 1000+ FREE Docs, Videos & Tests
    10M+ students study on EduRev
    © EduRev
    Education Revolution
    Signup to see your scores go up within 7 days!
    Access 1000+ FREE Docs, Videos and Tests
    Takes less than 10 seconds to signup