JEE Chemistry Questions

Solutions

Which one of the following aqueous solutions will exhibit highest boiling point?

  1. 0.01 M KNO3
  2. 0.015 M urea
  3. 0.01 M Na2SO4
  4. 0.015 M glucose

Solutions

Equimolal solutions in the same solvent have

  1. Same boiling and same freezing points.
  2. Different boiling and different freezing points.
  3. Same freezing point but different boiling point.
  4. Same boiling point but different freezing point.

Solutions

Two solutions of a substance (non electrolyte) are mixed in the following manner:

480 ml of 1.5 M first solution + 520 mL of 1.2 M second solution

What is the molarity of the final mixture?

  1. 2.70 M
  2. 1.50 M
  3. 1.344 M
  4. 1.20 M

Solutions

Benzene and toluene form nearly ideal solutions. At 20°C, the vapour pressure of benzene is 75 torr and that of toluene is 22 torr. The partial vapour pressure of benzene at 20°C for a solution containing 78 g of benzene and 46 g of toluene in torr is

  1. 25
  2. 37.5
  3. 50
  4. 53.5

Solutions

In a 0.2 molal aqueous solution of a weak acid HX, the degree of ionization is 0.3. Taking Kf for water as 1.85, the freezing point of the solution will be nearest to

  1. – 0.480 °C
  2. – 0.360 °C
  3. – 0.260 °C
  4. + 0.480 °C

States Matter

How many unit cells are present in a cube-shaped ideal crystal of NaCl of mass 1.00 g? [Atomic masses: Na = 23, Cl = 35.5]

  1. 2.57 × 1021
  2. 1.28 × 1021
  3. 1.71 × 1021
  4. 5.14 × 1021

States Matter

In a compound, atoms of element Y form ccp lattice and those of element X occupy 2/3rd of tetrahedral voids. The formula of the compound will be

  1. X2Y
  2. X3Y4
  3. X4Y3
  4. X2Y3

Gaseous State

If Z is a compressibility factor, van der Waals equation at low pressure can be written as

  1. Z = 1+Pb/RT
  2. Z = 1-a/(VRT)
  3. Z = 1+RT/Pb
  4. Z = 1-Pb/RT

Gaseous State

Equal masses of methane and oxygen are mixed in an empty container at 25°C. The fraction of the total pressure exerted by oxygen is

  1. 1/2
  2. 1/3
  3. 2/3
  4. (1/3) * (273/298)

States Matter

Lithium forms body centred cubic structure. The length of the side of its unit cell is 351 pm. Atomic radius of the lithium will be

  1. 75 pm
  2. 152 pm
  3. 240 pm
  4. 300 pm

Gaseous State

According to the kinetic theory of gases, in an ideal gas, between two successive collisions a gas molecule travels

  1. in a straight line path
  2. in a wavy path
  3. in a circular path
  4. with an accelerated velocity

Gaseous State

In van der Waals equation of state of the gas law, the constant b is a measure of

  1. volume occupied by the molecules
  2. intermolecular attraction
  3. intermolecular repulsions
  4. intermolecular collisions per unit volume

Chemical Bonding

The correct order of bond angles (smallest first) in H2S, NH3, BF3 and SiH4 is

  1. H2S < NH3 < SiH4 < BF3
  2. NH3 < H2S < SiH4 < BF3
  3. H2S < SiH4 < NH3 < BF3
  4. H2S < NH3 < BF3 < SiH4

Chemical Bonding

The bond order in NO is 2.5 while that in NO+ is 3. Which of the following statements is true for these two species?

  1. Bond length is unpredictable
  2. Bond length in NO+ is equal to that in NO
  3. Bond length in NO+ is greater than in NO
  4. Bond length in NO is greater than in NO+

Chemical Bonding

The molecule having smallest bond angle is

  1. AsCl3
  2. PCl3
  3. SbCl3
  4. NCl3

Chemical Bonding

A square planar complex is formed by hybridisation of which atomic orbitals?

  1. s, px, py, pz
  2. s, px, py, pz, d
  3. d, s, px, py
  4. s, px, py, pz, d, d

Atomic Structure

In Bohr series of lines of hydrogen spectrum, the third line from the red end corresponds to which one of the following interorbit jumps of the electron for Bohr orbits in an atom of hydrogen?

  1. 2 → 5
  2. 4 → 1
  3. 5 → 2
  4. 3 → 2

Atomic Structure

Which of the following sets of quantum numbers is correct for an electron in 4f orbital?

  1. n = 4, l = 4, m = –4, s =-1/2
  2. n = 4, l = 3, m = +4, s =+1/2
  3. n = 3, l = 2, m = –2, s =+1/2
  4. n = 4, l = 3, m = +1, s =+1/2

Atomic Structure

Which of the following statements in relation to the hydrogen atom is correct?

  1. 3s orbital is lower in energy than 3p orbital
  2. 3s, 3p and 3d orbitals all have the same energy
  3. 3s and 3p orbitals are of lower energy than 3d orbital
  4. 3p orbital is lower in energy than 3d orbital

Atomic Structure

Consider the following nuclear reactions:

23892M → XYN + 242He  ;  XYN → ABL + 2β+

The number of neutrons in the element L is

  1. 146
  2. 144
  3. 142
  4. 140

Stoichiometry

How many moles of magnesium phosphate, Mg3(PO4)2 will contain 0.25 mole of oxygen atoms?

  1. 2.5 x 10-2
  2. 0.02
  3. 1.25 x 10-2
  4. 3.125 x 10-2

Stoichiometry

If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

  1. decrease twice
  2. remain unchanged
  3. increase two fold
  4. be a function of the molecular mass of the substance

Stoichiometry

With increase of temperature, which of these changes?

  1. molality
  2. molarity
  3. mole fraction
  4. weight fraction of solute

Stoichiometry

What volume of hydrogen gas, at 273 K and 1 atm. pressure will be consumed in obtaining 21.6 g of elemental boron (atomic mass = 10.8) from the reduction of boron trichloride by hydrogen?

  1. 89.6 L
  2. 67.2 L
  3. 44.8 L
  4. 22.4 L

Stoichiometry

Number of atoms in 558.5 gram Fe (atomic weight of Fe = 55.85 g mol–1) is

  1. twice that in 60 g carbon
  2. 558.5 × 6.023 × 1023
  3. half that in 8 g He
  4. 6.023 × 1022

Stoichiometry

In the reaction,

2Al (s) + 6HCl (aq) → 2Al3+ (aq) + 6Cl (aq) + 3H2 (g)

  1. 6 L HCl (aq) is consumed for every 3 L H2(g) produced
  2. 11.2 L H2(g) at STP is produced for every mole HCl (aq) consumed
  3. 33.6 L H2(g) is produced regardless of temperature and pressure for every mole Al that reacts
  4. 67.2 L H2(g) at STP is produced for every mole Al that reacts

Stoichiometry

The molecular formula of a commercial resin used for exchanging ions in water softening is C8H7SO3Na (Mol. Wt. 206). What would be the maximum uptake of Ca2+ ions by the resin when expressed in mole per gram resin?

  1. 2/309
  2. 1/103
  3. 1/206
  4. 1/412

Atomic Structure

Which of the following is the energy of a possible excited state of hydrogen?

  1. - 6.8 eV
  2. - 3.4 eV
  3. + 6.8 eV
  4. + 13.6 eV

Periodic Properties

The ionic radii (in Å) of N3–, O2– and F are respectively

  1. 1.36, 1.71 and 1.40
  2. 1.71, 1.40 and 1.36
  3. 1.71, 1.36 and 1.40
  4. 1.36, 1.40 and 1.71

df-Block

The color of KMnO4 is due to

  1. d – d transition
  2. L → M charge transfer transition
  3. σ – σ* transition
  4. M → L charge transfer transition

Everyday Life Chem

Which of the following compounds is not an antacid?

  1. Cimetidine
  2. Phenelzine 
  3. Ranitidine
  4. Aluminium hydroxide

Isolation Metals

In the context of the Hall-Heroult process for the extraction of Al, which of the following statements is false?

  1. Al2O3 is mixed with CaF2 which lowers the melting point of the mixture and brings conductivity
  2. Al3+ is reduced at the cathode to form Al
  3. Na3AlF6 serves as the electrolyte
  4. CO and CO2 are produced in this process

Polymers

Which polymer is used in the manufacture of paints and lacquers?

  1. Glyptal
  2. Polypropene
  3. Poly vinyl chloride
  4. Bakelite

Stoichiometry

In a compound C, H and N atoms are present in 9:1:3.5 by weight. Molecular weight of compound is 108. Molecular formula of compound is

  1. C9H12N3
  2. C3H4N
  3. C6H8N2
  4. C2H6N2

Atomic Structure

Number of atoms in 558.5 gram Fe (atomic weight of Fe = 55.85 g mol–1) is

  1. twice that in 60 g carbon
  2. half that in 8 g He
  3. 6.023 × 1022
  4. 558.5 × 6.023 × 1023

Atomic Structure

The de Broglie wavelength of a tennis ball of mass 60 g moving with a velocity of 10 metres per second is approximately (Planck's constant, h = 6.63 × 10–34 Js)

  1. 10–16 metres
  2. 10–31 metres
  3. 10–33 metres
  4. 10–25 metres

Chemical Bonding

Which one of the following compounds has the smallest bond angle in its molecule?

  1. NH3
  2. SH2
  3. SO2
  4. OH2

States Matter Gaseous State

For an ideal gas, number of moles per litre in terms of its pressure P, gas constant R and temperature T is

  1. P/RT
  2. PT/R
  3. RT/P
  4. PRT

Chemical Thermodynamics

The enthalpy change for a reaction does not depend upon the

  1. use of different reactants for the same product.
  2. nature of intermediate reaction steps.
  3. physical states of reactants and products.
  4. difference in initial or final temperatures of involved substances.

Hydrocarbons

Butene-­1 may be converted to butane by reaction with

  1. Zn-Hg
  2. Sn-HCl
  3. Zn-­HCl
  4. Pd/H2

Hydrocarbons Organic Halogens

On mixing a certain alkane with chlorine and irradiating it with ultraviolet light, it forms only one monochloroalkane. This alkane could be

  1. neopentane
  2. pentane
  3. propane
  4. isopentane

Organic Halogens

2-­Methylbutane on reacting with bromine in the presence of sunlight gives mainly

  1. 2-­bromo­-2-­methylbutane
  2. 1-­bromo-­3-­methylbutane
  3. 2-­bromo-­3-­methylbutane
  4. 1-­bromo-­2-­methylbutane

Organic Nitrogen

Presence of a nitro group in a benzene ring

  1. deactivates the ring towards nucleophilic substitution
  2. activates the ring towards electrophilic substitution
  3. renders the ring basic
  4. deactivates the ring towards electrophilic substitution

Hydrocarbons Organic Halogens

The reaction of toluene with Cl2 in presence of FeCl3 gives predominantly

  1. benzoyl chloride
  2. m-­chlorobenzene
  3. benzyl chloride
  4. o­- and p­-chlorotoluene

Hydrocarbons Organic Halogens

Which of the following reactions will yield 2, 2-­dibromopropane?

  1. C2H2 + 2HBr →
  2. CH3CHCH2 + 2HBr →
  3. CH3CHCHBr + HBr →
  4. CH3CCH + 2HBr →

Hydrocarbons

The hydrocarbon which can react with sodium in liquid ammonia is

  1. CH3CHCHCH3
  2. CH3CH2C≡CCH2CH3
  3. CH3CH2CH2C≡CCH2CH2CH3
  4. CH3CH2C≡CH

Hydrocarbons Basic Organic

The alkene that exhibits geometrical isomerism is

  1. 2-methyl propene
  2. 2 methyl 2 butene
  3. 2-Butene
  4. propene

Basic Organic

The IUPAC name of neopentane is

  1. 2 – methylpropane
  2. 2, 2 – dimethylpropane
  3. 2 – methylbutane
  4. 2, 2 – dimethylbutane

Hydrocarbons Organic Oxygen

One mole of a symmetrical alkene on ozonolysis gives two moles of an aldehyde having a molecular mass of 44 u. The alkene is

  1. 1-butene
  2. 2-butene
  3. propene
  4. ethene

Hydrocarbons Organic Oxygen

Ozonolysis of an organic compound gives formaldehyde as one of the products. This confirms the presence of

  1. an acetylenic triple bond
  2. a vinyl group
  3. two ethylenic double bonds
  4. an isopropyl group