Class - 10+1
Chemistry Paper 2024
Time: 3 hrs Max Marks: 70
Note: All questions are compulsory.
Section - (A)
1. Multiple Choice Questions :
- In NO₃⁻ ion, the number of bond pairs and lone pairs of electron on Nitrogen atom are
(a) 2, 2 (b) 3, 1 (c) 1, 3 (d) 4, 0 - The electronic configuration of the outermost shell of the most electronegative element is
(a) 2s²2p⁵ (b) 3s²3p⁵ (c) 4s²4p⁵ (d) 5s²5p⁵ - The maximum number of elements in 3rd period is
(a) 8 (b) 18 (c) 32 (d) between 8 and 18 - The correct order of increasing radii of the elements Na, Si, Al and P is
(a) Si, Al, P, Na (b) Al, Si, P, Na (c) P, Si, Al, Na (d) Al, P, Si, Na - The anion O⁻ is isoelectronic with
(a) N²⁻ (b) F⁻ (c) N³⁻ (d) Ne - The designation of an orbital with n = 4 and l = 3 is
(a) 4s (b) 4p (c) 4d (d) 4f - How many spherical nodes are present in 4s orbital in a hydrogen atom?
(a) 0 (b) 1 (c) 2 (d) 3 - 1 mole of methane contains
(a) 6.02 x 10²³ atoms of H (b) 4 g atoms of hydrogen
(c) 1.81 x 10²² molecules of methane (d) 3.00 g of carbon - The correct ground state electronic configuration of chromium (Z = 24) is
(a) [Ar] 3d⁵4s¹ (b) [Ar] 3d⁶4s¹ (c) [Ar] 3d⁴4s² (d) [Ar] 4s²4p⁵ - The tendency towards complex formation is maximum in
(a) S-block elements (b) P-block elements
(c) d-block elements (d) None of these - The recently discovered element Meitnerium (Z = 109) belongs to
(a) S-block (b) P-block (c) d-block (d) f-block - The linear structure is possessed by
(a) BF₃ (b) NO₂⁻ (c) CO₂ (d) None of these - Identify a molecule which does not exist.
(a) C₂ (b) O₂ (c) He₂ (d) Li₂ - The structure of IF₇ is
(a) Square pyramid (b) Trigonal bipyramid
(c) Octahedral (d) Pentagonal bipyramid - The hybridisation of C involved in acetylene is
(a) sp² (b) sp³ (c) sp (d) dsp² - Which of the following molecules does not contain lone pairs of electrons?
(a) NH₃ (b) PF₅ (c) H₂O (d) SF₄ - The angle between covalent bonds is maximum in
(a) CH₄ (b) BF₃ (c) PF₅ (d) NH₃ - Which of the following has dipole moment?
(a) CCl₄ (b) C₂H₂ (c) BF₃ (d) NH₃
Passage:
Modern periodic table is essentially the consequence of the periodic variation in electronic configurations of atoms which determine the physical and chemical properties of the elements and compounds. In this table the elements are arranged in horizontal rows called periods and vertical columns called groups.
- How many periods and groups are present in the modern periodic table?
- What is the basic difference in approach between the Mendeleev's periodic law and the Modern periodic law?
- An element has the outer electronic configuration 3s²3p⁶. To which period and group does this element belong?
- How many elements are present in the Lanthanide series?
- Five elements A, B, C, D and E have the atomic numbers 6, 12, 32, 36 and 14 respectively. Which of these belong to same group?
True/False :
- Potassium has higher ionisation enthalpy than sodium. (T/F)
- Among O, O⁻ and O²⁻ oxygen has the largest size. (T/F)
- The bond angle follows the order NH₄⁺ > NH₃ > NH₂⁻.
- The bond order of CO molecule is 2.5.
- Molarity of a solution changes with temperature but molality does not.
Section - (B)
Each question carries 2 marks:
2. Answer the following:
- Define:
- (a) Molarity
- (b) Paul’s Exclusion Principle
- What is the significance of the term isolated gaseous atom and ground state? State while defining the ionisation enthalpy and electron gain enthalpy.
- Explain why
- (i) Be has higher ΔHi than B
- (ii) O has lower ΔHi than N and F.
- Write down resonating structure of CO₃²⁻ and SO₃²⁻.
- Differentiate between Emission spectrum and Absorption spectrum.
- What is the concentration of sugar C₁₂H₂₂O₁₁ in mole L⁻¹ if its 20 g are dissolved in enough water to make a volume upto 2 L?
- Differentiate orbit and orbital.
- The mass of an electron is 9.1 x 10⁻³¹ Kg. If its kinetic energy is 3.0 x 10⁻²⁵J. Calculate its wavelength.
OR
- Calculate the uncertainty in the velocity of a wagon of mass 2000 Kg whose position is known to an accuracy of ±1 cm.
- The elements Z = 117 and 118 have recently been discovered and named. In which family group would you place these elements and also give electronic configuration in each case. Name these elements.
Section - (C)
- Define ionisation enthalpy. Explain it variation along a period and down a group.
- Explain the structure of PCl₅ on the basis of VSEPR theory.
OR
- The energy associated with the first orbit in the hydrogen atom is -2017 x 10⁻¹⁸J atom⁻¹. What is the energy associated with the fifth orbit?
- Calculate the radius of Bohr's fifth orbit for hydrogen atom.
- Draw molecular orbital diagram of oxygen molecule.
- What is meant by the term bond order? Calculate the bond order of N₂ and N₂⁻.
OR
OR
- 50 Kg of N₂ (g) and 10.0 Kg of H₂ (g) are mixed to produce NH₃ (g).
(a) Calculate the NH₃ (g) formed.
(b) Identify the limiting reagent in this reaction if any.
(c) Which out of NH₄⁺ and NF₃ has higher dipole moment and why?
Section - (D)
- (a) What is hybridisation? Explain the structure of Ethene on the basis of hybridisation.
(b) Write the electronic configuration of the following ions:
(i) F⁻ (ii) Na⁺
OR
- (a) Determine the empirical formula of an oxide of iron which has 69.9% iron and 30.1% dioxygen by mass. (Atomic mass: Fe = 58.5 μ = 16 μ).
(b) A solution is prepared by dissolving 2 g of substance A in 18 g of water. Calculate the mass percentage of solute. - Explain why cations are smaller and anions larger in radii than their parent atoms.
(i) Boron forms [BF₄]⁻ while aluminium forms AlF₆³⁻ in solution.
(ii) Lithium halides are covalent while halides of other members of group 1 are ionic in nature.
OR
- (a) Explain the following terms:
(i) Extensive properties (ii) Intensive properties (iii) Adiabatic process.
(b) If the density of methanol is 0.793 Kg L⁻¹ what is the volume needed for making 2.5 L of its 0.25 M solution?
