12 Chemistry Sp01
12 Chemistry Sp01
12 Chemistry Sp01
Class 12 - Chemistry
Sample Paper 01
Maximum Marks: 45
Time Allowed: 90 minutes
General Instructions:
Section A
1. What type of interaction hold the molecules together in a polar molecular solid?
a. London forces
b. Hydrogen bonding
c. Dipole - dipole interaction
d. Metallic bonding
2. Solubility of gas decreases with
a. Increase in pressure
b. Decrease in pressure
c. Increase in temperature
d. Decrease in temperature
3. Which gas is evolved when urea is treated with NaOH?
a. Nitrogen
b. Ammonia
c. Nitrous oxide
d. Laughing gas
4. Arrange the following compounds in increasing order of their boiling points.
a.
b. CH3CH2CH2CH2Br
c.
a. All of these
b. CrO3 in an anhydrous medium.
c. Heat in the presence of Cu at 573K.
d. Pyridinium chlorochromate.
6. In aqueous solution, amino acids behave like:
a. Carboxylic acids
b. Amines
c. Base
d. Salts
7. A metal has a body centered cubic crystal structure. The density of the metal is 5.96 g/cm3. Find the
volume of the unit cell if atomic mass of metal is 50.
a. 16.77
b. 2.786 × 10-23 cm3
c. 1.39 × 10-23 cm3
d. 5.572 × 10-23 cm3
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8. The plant cell will shrink when placed in:
a. A hypertonic solution
b. Water
c. An isotonic solution
d. A hypotonic solution
9. Which is used to produce smoke screens?
a. Zinc sulphide
b. Sodium carbonate
c. Zinc phosphide
d. Calcium phosphide
10. What is inversion of configuration?
a. Secondary butyl chloride
b. w-butyI bromide
c. tert-butyl chloride
d. iso-butyl iodide
11. Chloromethane on treatment with excess of ammonia yields mainly
a. Methanamine (CH3NH2)
b. Mixture containing all these in equal proportion
c. N–methylmethanamine (CH3—NH—CH3)
d. N, N-Dimethylmethanamine
12. The most appropriate structure for knowing about the sequence of nucleotides in the DNA chain is
a. tertiary structure
b. quaternary structure
c. secondary structure
d. primary structure
13. _______ is not an example of amorphous solids.
a. Plastic
b. Coke
c. Glass
d. Quartz
14. For ideal solution the enthalpy of mixing of the pure components to form the solution is
a. None of these
b.
c.
d.
15. Name the gas whose formula was established by Sorret.
a. Nitrous oxide
b. Oxygen
c. Ozone
d. Nitric oxide
16. Which of the following is an example of vic-dihalide?
a. 1,2-dichloroethane
b. Dichloromethane
c. Ethylidene chloride
d. Allyl chloride
17. One of the following is not a dihydroxy derivative of benzene.
a. Catechol
b. Phenol
c. Resorcinol
d. Quinol
18. Which of the following polymer is stored in the liver of animals?
a. Glycogen
b. Amylopectin
c. Amylose
d. Cellulose
19. Which of the following statements is not true?
a. Paramagnetic substances are weakly attracted by magnetic field.
b. Pairing of electrons cancels their magnetic moment in the diamagnetic substances.
c. The domains in antiferromagnetic substances are oppositely oriented with respect to each other.
d. Ferromagnetic substances cannot be magnetized permanently.
20. Which of the following types of compounds will have Vant Hoff factor = 1?
a. urea
b. None of these
c. NaCl
d. KNO3
21. Fluorine reacts with H2S to produce
a. SF6 and HF
b. SF4 and HF
c. SF6 ,S and HF
d. SF2 and HF4
22. Which of the following compounds has the highest boiling points?
a. CH3CH2CH2Cl
b. CH3CH2CH2CH2Cl
c. (CH3)3Cl
d. CH3CH(CH3)CH2Cl
23. Ketones react with Grignard reagent to produce _______.
a. tertiary alcohols
b. primary alcohols
c. secondary alcohols
d. None of these
24. Honey contains primarily
a. fat
b. minerals
c. lipid
d. carbohydrate
25. Reduction potentials of some ions are given below. Arrange them in decreasing order of oxidising
power.
Ion
a. carbohydrate
b. Vitamin
c. Protein
d. Lipid
29. HgO is treated with chlorine to form ______.
a. ClO2
b. Cl2O7
c. Cl2O6
d. Cl2O
30. Methyl bromide is converted into ethane by heating it in ether medium with ________.
a. Na
b. Al
c. Cu
d. Zn
31. The reagent used to distinguish between H2O2 and O3 is:
a. PbS
b. Bleaching powder
c. Starch and iodine
d. KMnO4
32. Hydrolysis of starch yields
a. sucrose
b. fructose
c. gluconic acid
d. glucose
33. Grignard reagent (CH3MgBr) on reaction CH3OH will give:
a. Aldehyde
b. Ethane
c. Ester
d. Methane
34. The use of pressure cooker reduces cooking time because it creates
a. High pressure
b. Low pressure
c. Low temperature
d. High temperature
35. Which of the following is the strongest Lewis base?
a. NF3
b. NCl3
c. NBr3
d. NI3
36. Which one of the following is a synthetic halogen compound?
a. Chloramphenicol
b. Diphenyl hydramine
c. Chloroquine
d. Omeprazole
37. An element forms a cubic unit cell with edge length 405 pm. Molar mass of this element is 2.7 × 10-
2 kg/mol and its density is given as 2.7 × 103 kg/m3. How many atoms of this elements are present per
unit cell?
a. 2
b. 4
c. 6
d. 1
38. By heating phenol with chloroform in alkali, it is converted into
a. Phenol benzoate
b. Salicylic acid
c. Anisole
d. Salicylaldehyde
39. Total number of voids in 0.5 mole of a compound which forms hexagonal close packed structure is
a. 9.033 × 1023
b. 3.011 × 1023
c. 12.044 × 1023
d. 6.022 × 1023
40. Molarity of the solution is
a. The number of moles of solute dissolved per litre of the solution
b. The number of moles of the solute dissolved per kilogram of the solvent
c. Number of grams of solute dissolved per kilogram of solvent
d. The number of gram mole of the solute dissolved per ml. of the solution
41. Which of the following elements can be involved in p –d bonding?
a. Carbon
b. Nitrogen
c. Boron
d. Phosphorus
42. In the following compounds:
d. alcohols
Question No. 53 to 55 are based on the given text. Read the text carefully and answer the
questions:
Fluorine, chlorine, bromine, iodine and astatine are members of Group 17. These are collectively
known as the halogens. The halogens are highly reactive non-metallic elements. Fluorine and chlorine
are fairly abundant while bromine and iodine less so. Fluorine is present mainly as insoluble
fluorides and small quantities are present in the soil, river water plants and bones and teeth of
animals. All these elements have seven electrons in their outermost shell (ns2 np5 ). The halogens have
the smallest atomic radii in their respective periods due to maximum effective nuclear
charge. Halogens display smooth variations in their physical properties. Fluorine and chlorine are
gases, bromine is a liquid and iodine is a solid. Their melting and boiling points steadily increase with
atomic number. All halogens are coloured. F2, has yellow, Cl2, greenish-yellow, Br2, red and I2, violet
colour.
53. Which of the following is the correct set of increasing atomic radius
a. F > I > Cl > Br
b. F > Cl > Br > I
c. Br > I > F > Cl
d. Cl > Br > I > F
54. ________ is the most electronegative element in the periodic table.
a. Br
b. F
c. Cl
d. I
55. Why negative electron gain enthalpy of fluorine is less than that of chlorine?
a. Due to the small size of fluorine atom
b. Due to strong interelectronic repulsions in the relatively small 2p orbitals of fluorine
c. Both (a) and (b)
d. None of these
a. (a)
b. (d)
c. (c)
d. (b)
Class 12 - Chemistry
Sample Paper 01
Solution
Section A
1. (c) Dipole - dipole interaction
Explanation: Polar molecule will act as a dipole.
2. (c) Increase in temperature
Explanation: Because of increase in kinetic energy of gas molecules with temperature their tendency
to escape from the liquid will increase.
3. (b) Ammonia
Explanation: Urea on reaction with NaOH liberates ammonia.
NH2CONH2 + 2NaOH Na2CO3 + 2NH3
4. (a) (c) < (a) < (b)
Explanation: The bolling points of isomeric haloalkanes decrease with an increase in branching as
with an increase in branching surface area decreases which leads to a decrease in intermolecular
forces. Hence, the increasing order of their boiling points is c < a < b.
5. (a) All of these
Explanation: Oxidation of alcohols to aldehydes is partial oxidation; aldehydes are further
oxidized to carboxylic acids. Conditions required for making aldehydes are heat and distillation.
In aldehyde formation, the temperature of the reaction should be kept above the boiling point of the
aldehyde and below the boiling point of the alcohol. Reagents useful for the transformation of primary
alcohols to aldehydes are normally also suitable for the oxidation of secondary alcohols to ketones.
These include:
Chromium-based reagents, such as Collins reagent (CrO3·Py2)
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PDC or PCC.
Heat in the presence of Cu at 573K.
6. (d) Salts
Explanation: Amino acids are water-soluble, high melting solids and behave like salts rather than
simple amines or carboxylic acids. This behaviour is due to the presence of both acidic (carboxyl
group) and basic (amino group) groups in the same molecule. In aqueous solution, the carboxyl group
can lose a proton and amino group can accept a proton, giving rise to a dipolar ion known as zwitter
ion. This is neutral but contains both positive and negative charges.
7. (b) 2.786 × 10-23 cm3
Explanation:
Explanation: Calcium phosphide is used to produce smoke screens. Calcium phosphide hydrolyses to
liberate phosphine which burns in air to form P4O10 which acts as the smoke screens.
Ca3P2(s) + 6H2O(l) 3Ca(OH)2(s)+2PH3(g)
4PH3(l) + 8O2(g) P4O10(g) + 6H2
10. (a) Secondary butyl chloride
Explanation: Secondary butyl chloride is optically active because it has chiral carbon atom marked*
Section B
26. (a) 4
Explanation: Two-dimension close-packed structures, where rows of identical spherical molecules are
stacked on top of each other, can be done in two ways, square and hexagonal. In a square close-packed
structure, the second row is stacked just above the first row, and the spheres are aligned horizontally
and vertically as the way mentioned above. If we observe a sphere in this arrangement, it is
surrounded by four spheres that are in direct contact with it. Joining the centers of the four spheres
also forms a square, thus giving the term square close-packed structure in two- dimension. Thus by
definition of coordination number, a sphere in close-packed structure is 4.
27. (c) Molality
Explanation: Molality
28. (a) carbohydrate
Explanation: It is aldohexose. An aldohexose is a hexose with an aldehyde group on one end.it is
naturally occurring in nature and is found in fruits.
29. (d) Cl2O
Explanation: HgO + 2Cl2 HgCl2 + Cl2O
Mercury(II) oxide reacts with chlorine to produce mercury(II) chloride and dichlorine monoxide.
Mercury(II) oxide is in the suspension form. This reaction takes place at a temperature near 0°C in the
liquid tetrachloromethane.
30. (a) Na
Explanation: 2CH3Br + 2Na CH3CH3 + 2NaBr
31. (d) KMnO4
Explanation: H2O2 can decolorize the color of KMnO4.
H2O2 + KMnO4 O2 + MnO2 + KOH + H2O
Ozone can activate soluble or insoluble Mn into permanganate ion but will not oxidize it further. So no
effect.
32. (d) glucose
Explanation: Glucose is the monomer of many of the larger carbohydrates, namely starch,
cellulose. Hydrolysis of starch gives glucose.
33. (d) Methane
Explanation: CH3MgBr reacts with CH3OH and form CH4.
Grignard Reagent act as both base as well as a nucleophile. In the presence of alcohol, H2O or other
groups having acidic hydrogen Grignard reagent act as base and abstract acidic H.
34. (a) High pressure
Explanation: High pressure increases the boiling point of water so it reduces the cooking time.
35. (d) NI3
Explanation: The strongest lewis base is NI3 due to lower electronegativity of I. So the tendency of
trihalides of N decreases from NI3 > NBr3 > NCl3 > NF3 due to increase in electronegativity from I to F.
36. (c) Chloroquine
Explanation: Chloroquine is a synthetic halogen compound. It is used for the treatment of malaria.
37. (b) 4
Explanation:
= 4.004
= 4
38. (d) Salicylaldehyde
Explanation: Salicylaldehyde
39. (a) 9.033 × 1023
Explanation: Number of atoms in 1 mole of compound =
Number of atoms in 0.5 mole of compound = 0.5 × = 3.011 ×
For a hexagonal close−packed structure,
Number of octahedral voids = number of atoms in close packaging
Therefore, the Number of octahedral voids = 3.011 ×
and Number of tetrahedral voids = 2 × number of atoms in close packaging
so, Number of tetrahedral voids = 2 × 3.011 × = 6.022 ×
Total number of voids = Tetrahedral void + octahedral void
= (6.022 + 3.011) ×
= 9.033 ×
40. (a) The number of moles of solute dissolved per litre of the solution
Explanation: Molarity
41. (d) Phosphorus
Explanation: Phosphorus can be involved in p - d bonding due to the presence of vacant d orbitals
Carbon, Nitrogen, and Boron does not have d orbitals.
42. (c) (iv) > (iii) > (i) > (ii)
Explanation: (iv) > (iii) > (i) > (ii)
43. (b) HgS
Explanation: HgS is only soluble in aqua regia. Aqua regia is a mixture of concentrated HCl and
concentrated HNO3 in ratio 3:1. The solubilization turns Hg in HgCl42-, a complex called
chloromercurate which is stable in water.
3HgS + 2NO3- + 12Cl- + 8H3O+ 3HgCl42- + 2NO + 12H2O + 3S
44. (c) All of these
Explanation: Complete hydrolysis of RNA yields a pentose sugar, phosphoric acid and nitrogen
containing heterocyclic compounds (called bases). In RNA molecule, the sugar moiety is β-D-ribose.
45. (c) A is true but R is false.
Explanation: A is true but R is false.
46. (d) A is false but R is true.
Explanation: Haloalkanes react with AgCN to form alkyl isocyanides as the main product while KCN
forms alkyl cyanides as the chief product.
47. (b) Both assertion and reason are wrong statements.
Explanation: Glycine can be synthesized by the body and is a non-essential amino acid.
48. (a) Both A and R are true and R is the correct explanation of A.
Explanation: Both A and R are true and R is the correct explanation of A.
49. (b) Both A and R are true but R is not the correct explanation of A.
Explanation: The FCC has maximum packing efficiency of 74% which in the case of BCC is 68% and
Simple cubic has 52.4%. FCC has coordination number 12.
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Section C
50. (d) Molarity changes with temperature
Explanation: Molarity depends upon Volume of solution which changes with Temperature.
51. (b) Chloramphenicol