Question Paper JEE - Mains
1. There are two ums. Urn A has 3 distinct red balls and urn B has 9 distinct blue balls. From each urn, two balls are taken out at random and then transferred to the other. The number of ways in which this can be done, is
(a) 3
(b) 36
(b) 36
(c) 66
(d) 108
(d) 108
Ans. d
2. The polymer containing strong intermolecular forces e.g., hydrogen bonding, is
(a) teflon
(b) nylon-66
(c) polystyrene
(d) natural rubber
Ans. b
3. The edge length of a face centered cubic cell of an ionic substance is 508 pm. If the radius of the cation is 110 pm, the radius of the anion is
3. The edge length of a face centered cubic cell of an ionic substance is 508 pm. If the radius of the cation is 110 pm, the radius of the anion is
(a) 288 pm
(b) 398 pm
(b) 398 pm
(c) 618 pm
(d) 144 pm
Ans. d
4. One mole of a symmetrical alkene on ozonolysis gives two moles of an aldehyde having a molecular mass of 44 u. The alkene is
(d) 144 pm
Ans. d
4. One mole of a symmetrical alkene on ozonolysis gives two moles of an aldehyde having a molecular mass of 44 u. The alkene is
(a) propene
(b) 1-butene
(b) 1-butene
(c) 2-butene
(d) ethene
(d) ethene
Ans. c
5. If sodium sulphate is considered to be completely dissociated into cations and anions in aqueous solution, the change in freezing point of water (DTf), when 0.01 mole of sodium sulphate is dissolved in 1 kg of water is (Kf = 1.86 K kg mol–1)
(a) 0.0372 K
(b) 0.0558 K
(b) 0.0558 K
(c) 0.0744 K
(d) 0.0186 K
(d) 0.0186 K
Ans. b
6. From amongst the following alcohols, the one that would react fastest with conc. HCl and anhydrous ZnCl2, is
(a) 2-butanol
(b) 2-methylpropan-2-ol
(b) 2-methylpropan-2-ol
(c) 2-methylpropanol
(d) 1-butanol
(d) 1-butanol
Ans. b
7. The energy required to break one mole of Cl—Cl bonds in Cl2 is 242 kJ mol–1. The longest wavelength of light capable of breaking a single Cl—Cl bond is (c = 3t × 108 ms–1 and NA = 6.02 × 1023 mol–1)
7. The energy required to break one mole of Cl—Cl bonds in Cl2 is 242 kJ mol–1. The longest wavelength of light capable of breaking a single Cl—Cl bond is (c = 3t × 108 ms–1 and NA = 6.02 × 1023 mol–1)
(a) 594 nm
(b) 640 nm
(b) 640 nm
(c) 700 nm
(d) 494 nm
(d) 494 nm
Ans. d
8. Ionisation energy of He+ is 19.6 × 10–18 J atom–1. The energy of the first stationary state (n = 1) of Li2+ is
(a) 4.41 × 10–16 J atom–1
(b) –4.41 × 10–17 J atom–1
(c) –2.2 × 10–15 J atom–1
(d) 8.82 × 10–17 J atom–1
Ans. b
9. The speed of light in the medium is
9. The speed of light in the medium is
(a) minimum on the axis of the beam
(b) the same everywhere in the beam
(c) directly proportional to the intensity l
(d) maximum on the axis of the beam
Ans. a
10. As the beam enters the medium, it will
10. As the beam enters the medium, it will
(a) diverge
(b) converge
(c) diverge near the axis and converge near the periphery
(d) travel as a cylindrical beam