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- CBSE PREVIOUS YEAR QUESTION PAPERS (MARCH)- 2013 (SOLVED)(Set II )
CBSE PREVIOUS YEAR QUESTION PAPERS (MARCH)- 2013 (SOLVED)(Set II )
CBSE PREVIOUS YEAR QUESTION PAPERS (MARCH)- 2013 (SOLVED)
CHEMISTRY
Set II
Maximum Marks: 70
Time allowed : 3 hours
General Instructions:
(i) All questions are compulsory.
(ii) Questions number 1 to 8 are very short- answer questions and carry 1 mark each.
(iii) Questions number 9 to 18 are short – answer questions and carry 3 marks each.
(iv) Questions number 19 to 27 are also short- answer questions and carry 3 marks each.
(v) Question number 28 to 30 are long- answer questions and carry 5 marks each.
(vi) Use Log Tables, if necessary. Use of calculator is not allowed.
1. Write the structure of 2 - aminotoluene.
2. Which aerosol depletes ozone layer ?
3. Name two poisonous gases which can be prepared from chlorine gas.
4. Ethanal is soluble in water. Why ?
5. Write the IUPAC name of the following compound :
CH3-CH-CH2-CH-CH3
/ /
Br CI
6. Write the structure of n-methylethanamine.
7. Write the name of linkage joining two amino acids.
8. Give one example of a condensation polymer.
9. (a) Why does presence of excess of lithium makes LiCl crystals pink ?
(b) A solid with cubic crystal is made of two elements P and Q. Atoms of Q are at the corners of the cube and P at the body-centre. What is the formula of the compound ?
10.Aluminium crystallizes in an fcc structure. Atomic radius of the metal is 125 pm. What is the length of the side of the unit cell of the metal ?
11. The standard electrode potential (E°) for Daniel cell is 1.1 V. Calculate the ΔG° for the reaction
Zn(s)Cu^2(aq) →Zn^2(aq)Cu(s)
(1 F=96500 C mol^-1).
12. (a) For a reaction A B → P, the rate law is given by,
r = k [A]^1/2 ^2 .What is the order of this reaction ?
(b)A first order reaction is found to have a rate constant k = 5.5 × 10^-14 s^-1. Find the half life of the reaction.
13.(a) Name the method used for removing gangue from sulphide ores.
(b) How is wrought iron different from steel ?
14. Draw the structures of the following molecules :
(i) XeF6 (ii) H2S2O7
15. How are interhalogen compounds formed ? What general compositions can be assigned to them ?
16. Explain the mechanism of the following reactions
CH3-CH2-OH H/443K CH2=CH2H2O
17. Write the equations involved in the following reactions :
(i) Reimer - Tiemann reaction
(ii) Williamson's ether synthesis
18.Outline the principles of refining of metals by the following methods :
(i) Zone refining
(ii) Vapour phase refining
19.Define the following terms giving an example of each :
(i) Associated colloids
(ii) Lyophilic sol
(iii) Adsorption
20. What are the characteristics of the following colloids ? Give one example of each.
(i) Multimolecular colloids
(it) Lyophobic sols
(iii) Emulsions
21. Give reasons for the following :
(i) Where R is an alkyl group, R3P = O exists but R3N = O does not.
(ii) PbCl4 is more covalent than PbCl2.
(ii) At room temperature, N2 is much less reactive.
22. Write the main products of the following reactions :
(i)C6H5N2CI- H3PO2H2O?
(ii)Br2(aq)?
(iii)CH3-C-NH2 Br2NaOH?
//
O
23. Give reasons for the following :
(i) Ethyl iodide undergoes SN2 reaction faster than ethyl bromide.
(ii) 2-Butanol is optically inactive.
(iii) C- X bond length in halobenzene is smaller than C - X bond length in CH3-X.
24. Complete the following reactions:
(i)CH3CH2NH2CHCI3aIC.KOH→
(ii)C6H5N2CI- H2O/(Room Temp)
(iii)NH2HCI(aq.)→
25. (i) What class of drug is Ranitidine ?
(ii) If water contains dissolved Ca2 ions, out of soaps and synthetic detergents, which will you use for cleaning clothes ?
(iii) Which of the following is an antiseptic ?
0.2% phenol, 1% phenol.
26. Calculate the emf of the following cell at 25°C :
Ag (s)
Ag(10^-3 M)
Cu^2 (10^-1 M)
Cu (s)
Given
E°
cell = 0.46 V and log 10^n= n.
27.Give reasons for the following :
(i) Oxygen is a gas but sulphur is a solid.
(ii) O3 acts as a powerful oxidising agent.
(iii) BiH3 is the strongest reducing agent amongst all the hydrides of Group 15 elements.
28. (a) State Raoult's law for a solution containing volatile components. How does Raoult's law become
a special cause of Henry's law ?
(b) 1.00 g of a non-electrolyte solute dissolved in 50g of benzene lowered the freezing point of
benzene by 0-40 K. Find the molar mass of the solute. (Kffor benzene = 5.12 K kg mol^-1)
Or
(a) Define the following terms :
(i) Ideal solution
(ii) Azeotrope
(iii) Osmotic pressure
(b) A solution of glucose (C6H12O6) in water is labelled as 10% by weight. What would be the molality of the solution ?
(Molar mass of glucose = 180 g mol^-1)
29.(a) Give reasons for the following :
(i) Mn^3 is a good oxidising agent.
(ii)
E°
M^2/M values are not regular for first row transition metals (3d series).
(iii) Although 'F' is more electronegative than 'O', the highest Mn fluoride is MnF4, whereas the highest oxide is Mn2O7.
(b) Complete the following equations:
(i)2CrO4^2-2H^ →
(ii)KMnO4 heat
Or
(a) Why do transition elements show variable oxidation states ?
(i) Name the element showing maximum number of oxidation states among the first series of
transition metals from Sc (Z = 21) to Zn (Z =30).
(ii) Name the element which shows only 3oxidation state.
(b) What is lanthanoid contraction ? Name an important alloy which contains some of the
lanthanoid metals.
30.(a) How will you convert the following :
(i) Propanone to Propan-2-ol
(ii) Ethanal to 2-hydroxy propanoic acid
(iii) Toluene to benzoic acid
(b) Give simple chemical test to distinguish between :
(i) Pentan-2-one and Pentan-3-one
(ii) Ethanal and Propanal
Or
(a) Write the products of the following reactions :
(i)CH3-C-CH3 Zn-Hg/conc.HCI?
//
O
(ii)CH3-C-CIH2 Pd-BaSO4?
//
O
(iii)COOH Br2/FeBr3?
(b) Which acid of each pair here would you expect to be stronger?
(i)F-CH2-COOH or CI-CH2-COOH
(ii)OH or CH3COOH
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