CLASS:XI SUB: CHEMISTRY
1-Write the electronic configuration of Cu (Z=29) and Cr (Z=24).
2-Define the Pauli Exclusion Principle.
3-How many groups and periods are found in long form of the periodic table?
4-How many sigma and pi bonds are present in CH2= CH- CH=CH2 ?
5-Write any two properties of ionic compounds?
6-Using s, p, d and f notations describe the orbital with the following quantum numbers:
(a) N=2, l=1 (b) n=4, l=0 (c) n=5, l=3 (d) n=3, l=2
7-State the modern periodic law. Give any two limitations of modern periodic law.
8-Consider the following species:
N3- , O2- , Na+ , Mg2+ and Al3+
(i)What is common in them?
(ii)Arrange them in order of increasing ionic radii.
9-Out of NH3 and NF3 , which has higher dipole moment and why?
10-Calculate the wavelength, frequency and wave number of the light wave whose time period is 2x10-10 second. (Speed of light= 3x108 m/s)
11-Define the following terms :
(a)Heisenberg Uncertainty Principle (b) Hund’s rule of Maximum Multiplicity (c) (n+l) Rule
OR
(a)List two main differences between orbit and orbitals.
(b)State Aufbau’s principle. Arrange the following in order of increasing energy
(i) 3p (ii) 4s (iii) 2p (iv) 3d
12-(a)Write the general electronic configuration of P-block and d- block elements.
(b)State any four characteristics properties of d- block elements.
OR
(a)Write symbol and IUPAC name of the elements having atomic number 108 & 109.
(b)What is the electron gain enthalpy? Why electron gain enthalpy of Cl is more negative than F?
13-What is formal charge? Calculate the formal charge on carbon and oxygen atoms in CO32- ion.
14-(a) Define electronegativity.
(b)How does electronegativity vary along a period and down the group?
(c)Predict the period and group of the following elements:
(i) Si (Z=14) (ii) Mn (Z=25) (iii) Rb (Z=37)
15-What is hybridization? Discuss the shape and hybridization of PCl5 and SF6 molecules.
OR
What is the octet rule? Give any three limitations of octet rule.
16-What is meant by the term bond order? Calculate the bond order of N2, O2, O2+ and O2-.
OR
(a)Draw the molecular orbital diagram for O2 molecule.
(b)Predict the shape of the following covalent molecules on the basis of VSEPR Theory:
(i)BeF2 (ii)AlCl3 (iii)NH3 (iv)CH4
QUESTION PAPER
CLASS XII
SUBJECT : CHEMISTRY
MM :70TIME : 3 Hours
General Instructions:
a) All the questions are compulsory.
b) There are 26 questions in total.
c) Questions 1 to 5 are very short answer type questions and carry one mark each.
d) Questions 6 to 10 carry two marks each.
e) Questions 11 to 22 carry three marks each.
f) Questions 23 is value based question carrying four marks.
g) Questions 24 to 26 carry five marks each.
h) There is no overall choice. However, an internal choice has been provided in one question of
two marks, one question of three marks and all three questions in five marks each. You have
to attempt only one of the choices in such questions.
Use of calculators is not permitted. However, you may use log tables if necessary .
Q.1 which point defect in the crystals of a solid decrease it’s density?
Q.2 Nitrogen is relatively inert as compared to phosphorus. Why?
Q.3 Write the IUPAC name of CH3 – CH Cl - CH2 – CH=CH2 .
Q.4 What is an oil/water (O/W) type emulsion? Give an example.
Q.5 p – nitrophenol is more acidic than p – methylphenol.Why?
Q.6 What is the unit of rate constant for zero order reaction? Give an example of zero order reaction.
Q.7 Give a chemical test to distinguish between 10,20 and 30 amines. Write the reactions also.
OR
i) Alkyl amines are more basic than aryl amines. Explain.
ii) Why does aniline not undergo Friedel Craft reaction?
Q.8 a) Why does the tetrahedral complex of the type [MA2B2] not show geometrical isomerism?
b) What is an ambidentate ligand ? Give one example.
Q.9 Write the anode and cathode reactions and the overall reaction occurring in a lead storage battery.
Q.10 State Henry’s law correlating the pressure of a gas and its solubility in a solvent and mention twoapplications of the law.
Q.11 Silver crystallizes in fcc lattice. The edge length of it’s unit cell is 4.077 x 10 – 8 cm and it’s
density is 10.5 g/cm3. Calculate the atomic mass of silver.
Q.12 A reaction is second order in A and first order in B.
(i) Write the differential rate equation.
(ii) How is the rate affected on increasing the concentration of A three times?
(iii) How is the rate affected when the concentrations of both A and B are doubled?
OR
(i) A first order reaction takes 40 minutes for 30% decomposition. Calculate t1/2 for this reaction.
(Given log 1.428 = 0.1548)
(ii) What is the unit of rate constant k for zero order reaction?
Q.13 Define the following terms: (i) Mole fraction (ii) Van’t Hoff factor (iii) Colligative properties.
Q.14 Write the name ,state of hybridization ,the shape and magnetic behavior of following complexes : [CoCl4]2- , [Ni(CN)4]2- and [Cr(H2O)2(C2O4)2]-
Q.15a) Give an example of a bio degradable polymer.
b) Define thermoplastic and thermosetting polymers. Give one example of each.
Q.16Give a chemical equation for each of the following reactions:
(i) Williamson’s synthesis
(ii) Reimer-Tiemann reaction
Q.17 (a)State Kohlrausch’slaw of independent migration of ions.
(b) Calculatemfor acetic acid. Given that m(HCl) = 426 S cm2/ mol m(NaCl) = 126 S cm2/mol and m(CH3COONa) = 91 S cm2/ mol.
Q.18 How will you convert the following:
(i) Aniline to chlorobenzene
(ii) Ethanoic acid to methanamine
(iii) Benzene diazonium chloride to phenol
Q.19 a)Explain as to why haloarenes are much less reactive than haloalkanes towards nucleophilic substitution reactions.
b) Complete the following chemical equation:
CH3CH2CH= CH2 + HBr PEROXIDE
c) Which of the following shows faster SN2 reaction and why
CH3CH2CH2CH2I or CH3CH2CH2CH2Cl.
Q.20 What happens in the following activities and why?
(i) An electrolyte is added to a hydrated ferric oxide sol in water.
(ii) A beam of light is passed through a colloidal solution.
(iii)An electric current is passed through a colloidal solution.
Q.21.Describe the role of the following:
(i) NaCN in the extraction of silver from a silver ore
(ii) Iodine in the refining of titanium
(ii) Cryolite in the metallurgy of aluminium.
Q.22 Mention one use of each of the following:
(i) Ranitidine (ii) Aspartame (iii) Sodium benzoate
Q.23 Sheela did not eat fruits inspite of her mother’s constant reminders.She became very weak.Her room mate Sarita took her to a doctor.The doctor told her that fruits and vegetables contain vitaminswhich are essential for maintenance of normal growth and health of the people. Vitamins are required only in small amounts and should not be taken in excess.
Answer the following questions:
(i) Out of water soluble and fat soluble vitaminswhich can be stored in our body?
(ii) Name any two water soluble and two fat soluble vitamins.
(iii)Name any two values shown by Sarita?
Q.24a) Explain the following observations:
(i) With the same d-orbital configuration (d4) Cr2+ ion is a reducing agent while Mn3+ ion is an
oxidising agent.
(ii) Cu+ ion is not stable in aqueous solutions.
(iii) Among the 3d series of transition elements, the largest number of oxidation states is exhibitedby manganese.
b) Complete the following chemical reaction equations:
(i) MnO4(aq) + C2O42 (aq) + H+(aq)
(ii) Cr2O72(aq) + Fe 2(aq) + H+(aq)
R
a) How would you account for the following?
(i) Many of the transition elements and their compounds can act as good catalysts.
(ii) The metallic radii of the third (5d) series of transition elements are virtually the same as thoseof the corresponding members of the second series.
(iii) There is a greater range of oxidation states among the actinoids than among the lanthanoids.
(iv) Many of the transition elements are known to form interstitial compounds.
(v) There is a general increase in density from titanium (Z = 22) to copper (Z = 29).
Q.25(a) Complete the following equations:
(i) XeF2 PF5
(ii) Cl2( g) + NaOH (aq )
( hot and conc.)
(b) Explain the following observations:
(i) +3 oxidation state becomes more and more stable from As to Bi in the group.
(ii) Sulphur in vapour state exhibits paramagnetism.
(iii) Fluorine does not exhibit any positive oxidation state.
OR
(a) Draw the molecular structures of the following species:
(i) H3PO3 (ii) BrF3
(b) Explain the following observations:
(i) No distinct chemical compound of helium is known.
(ii) Phosphorus has a greater tendency for catenation than nitrogen.
(iii) In solutions of H2SO4 in water, the second dissociation constant Ka2, is less than the first
dissociation constant Ka1.
Q.26(a) Give simple chemical tests to distinguish between the following:
(i) Propanal and propanone
(ii) Benzaldehyde and acetophenone
(b) How would you obtain:
(i) But-2-enal from ethanal?
(ii) Butanoic acid from butanol?
(iii) Benzoic acid from ethylbenzene?
OR
(a) Describe the following reactions giving a chemical equation in each case:
(i) Cannizzaro reaction
(ii) Decarboxylation reaction
(b) Complete the following chemical equations:
KMnO4/KOH/Heat
(i) C6H5CH2CH3
(ii) + SOCl2 HEAT
C
COOH
(iii) C6H5CONH2 H2O/ HEAT