This document contains a chemistry exam with multiple choice and short answer questions. It provides instructions to convert the exam to PDF and submit it on Google Classroom. The exam contains 15 multiple choice questions covering topics like crystal structures, stoichiometric defects, and solution properties. It also includes 5 short answer and 2 long answer/case study questions involving concepts like colligative properties, crystal systems, and ideal/non-ideal solution behavior.
This document contains a chemistry exam with multiple choice and short answer questions. It provides instructions to convert the exam to PDF and submit it on Google Classroom. The exam contains 15 multiple choice questions covering topics like crystal structures, stoichiometric defects, and solution properties. It also includes 5 short answer and 2 long answer/case study questions involving concepts like colligative properties, crystal systems, and ideal/non-ideal solution behavior.
This document contains a chemistry exam with multiple choice and short answer questions. It provides instructions to convert the exam to PDF and submit it on Google Classroom. The exam contains 15 multiple choice questions covering topics like crystal structures, stoichiometric defects, and solution properties. It also includes 5 short answer and 2 long answer/case study questions involving concepts like colligative properties, crystal systems, and ideal/non-ideal solution behavior.
This document contains a chemistry exam with multiple choice and short answer questions. It provides instructions to convert the exam to PDF and submit it on Google Classroom. The exam contains 15 multiple choice questions covering topics like crystal structures, stoichiometric defects, and solution properties. It also includes 5 short answer and 2 long answer/case study questions involving concepts like colligative properties, crystal systems, and ideal/non-ideal solution behavior.
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XII(Chemistry).
Kendriya Vidyalaya Aizawl
PT-1(2020-21). General instructions:- 1. All questions are compulsory. 2. Convert it in PDF format and submit it in Google classroom
M.M. -40 Time- 90
minutes
MCQ type questions:- (1 Mark each)
1. What type of stoichiometric defect is shown by ZnS?
(a) Schottky defect (b) Frenkel defect (c) Both Frenkel and Schottky defects (d) Non-stoichiometric defect
2. The molal elevation constant depends upon
(a) nature of solute. (b) nature of the solvent. (c) vapour pressure of the solution. (d) enthalpy change
3.Out of molality (m), molarity (M), formality (F) and mole
fraction (x), those which are independent of temperature are (a) M, m (b) F, x (c) m, x (d) M, x
4.In which pair most efficient packing is present?
(a) hep and bcc (b) hep and ccp (c) bcc and ccp (d) bcc and simple cubic cell
5.Mole fraction of glycerine C3H5(OH)3 in solution containing 36
g of water and 46 g of glycerine is (a) 0.46 (b) 0.40 (c) 0.20 (d) 0.36
6.Which of the following condition is not satisfied by an ideal
solution? (a) ΔHmixing = 0 (b) ΔVmixing = 0 (c) Raoult’s Law is obeyed (d) Formation of an azeotropic mixture
7.Which one of the following is non-crystalline or amorphous?
(a) Diamond (b) Graphite (c) Glass (d) Common Salt 8. For a certain redox reaction, E° is positive. This means that (a) ΔG° is positive, K is greater than 1 (b) ΔG° is positive, K is less than 1 (c) ΔG° is negative, K is greater than 1 (d) ΔG° is negative, K is less than 1
9. Silver halides generally show
(a) Schottky defect (b) Frenkel defect (c) Both Frenkel and Schottky defects (d) cation excess defect
10. Cell reaction is spontaneous, when
(a) E°𝑟𝑒𝑑 is negative (b) ΔG° is negative (c) E°𝑜𝑥𝑖𝑑 is Positive (d) ΔG° is positive
11. Coordination number in ccp and hep arrangements of metal atoms are respectively. (a) 6, 6 (b) 12, 6 (c) 8, 6 (d) 12, 12
12.An example of body centered cube is
(a) Sodium (b) Magnesium (c) Zinc (d) Copper
13. What is the coordination number of Cl- in NaCl crystals
(a) 8 (b) 6 (c) 4 (d) 3 14. The number of octahedral sites per sphere in fcc structure is (a) 8 (b) 4 (c) 2 (d) 1 15. The crystal system of a compound with unit cell dimensions a = 0.387, b = 0.387 and c – 0.504 nm and α = ß = 90° and γ = 120° is (a) Cubic (b) Hexagonal (c) Orthorhombic (d) rhombohedral
Very short answer type questions:- ( 1 Mark each)
16.Write a distinguishing feature between a metallic solid and an ionic solid.
17. Why are crystalline solids anisotropic?
18. Give an example each of a molecular solid and an ionic solid. What type of stoichiometric defect is shown by AgCl?
19. What is the formula of a compound in which the element Y
forms ccp lattice and atoms of X occupy 1/3rd of tetrahedral voids? 20.What is meant by ‘reverse osmosis’? 21. What is molarity? 22. Why is the vapour pressure of liquid remains constant at room temperature? 23.Write one example of solid in gas and liquid in gas in gas solution. 24.Can you store AgCl solution in Zinc pot? 25. What is SHE? What is its electrode potential?
Short answer type questions :- (2 Mark each)
26. Write a distinguishing feature of a metallic solid compared to
an ionic solid. 27. Calculate the osmotic pressure of 0.25 M solution of urea at . R = 0.083 L bar/mol/k. 28.How is standard electrode potential of a cell related to :- 1) Equilibrium constant? 2) Gibbs free energy change. 29.What is the half cell potential for electrode in which .
30.Write an expression relating cell constant and conductivity?
Long answer type questions:- (5 Marks each)
31. Case Study Question 1:
Read the passage given below and answer the following questions:
The adjective, ‘crystalline’ when applied to solids, implies an
ideal crystal in which the structural units, termed as unit cells, are repeated regularly and indefinitely in three dimensions in space. The unit cell, containing at least one molecule has definite orientation and shape defined by the translational vectors, a, b and c. The unit cell therefore has a definite volume, V that contains the atoms and molecules necessary for generating the crystal. Every crystal can be classified as a member of one of the seven possible crystal systems or crystal classes that are defined by the relationship between the individual dimensions, a, b and c of the unit cell and between the individual angles, α, β, and γ of the unit cell. The structure of the given crystal may be assigned to one of the 7 crystal systems, to one of the 14 Brevais lattices, and to one of the 230 space groups. This uniquely define the possible ways of rearranging atoms in a three-dimensional solid, Based on these observations, seven crystal systems were identified: triclinic, monoclinic, trigonal or rhombohedral, tetragonal, hexagonal, rhombic or orthorhombic and cubic.
The following questions are multiple choice questions. Choose the
most appropriate answer:
(1) The crystal system of a compound with unit cell dimensions,
a=0.387 nm, b=0.387 nm and c=0.504 nm and α = β = 900 and γ=1200 is (a) cubic (b) hexagonal (c) orthorhombic (d) rhombohedral
(2) The unit cell with the structure given below represents ________ crystal system. (a) cubic (b) orthorhombic (c) tetragonal (d) trigonal
(3) In a triclinic crystal
(a) a = b = c, α = β = γ ≠ 900 (b) a ≠ b = c, α = β = γ = 900 (c) a ≠ b ≠ c, α ≠ β ≠ γ ≠ 900 (d) a ≠ b ≠ c, α = γ = 900 , β ≠ 900
(4) The unit cell with dimensions α = β = γ = 900 , a = b ≠ c is
(a) Why is the freezing point depression considered as a
colligative property? 1mark (b) The Cryoscopic constant of water is 1.86 km–1. Comment on this statement. 1mark (c) Calculate the amount of ice that will separate out on cooling solution containing 50 g of ethylene glycol in 200 g H2O to – 9.3°C. (Kf for water = 1.86 K kg mol–1) 3mark
33. 5marks a) Non-ideal solutions exhibit either positive or negative deviations from Raoult’s law. What are these deviations and why are they caused? Explain with one example for each type. 2marks
b) 18 g of glucose, C6H12O6 (Molar mass – 180 g mol-1) is
dissolved in 1 kg of water in a sauce pan. At what temperature will this solution boil? (Kb for water = 0.52 K kg mol-1, boiling point of pure water = 373.15 K) 3marks
