p-1 class xi chemistry 2010-2011

7/29/2019 P-1 Class XI Chemistry 2010-2011

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Name: Class & Sec: .. Roll No. :

ANNUAL EXAMINATION (2010-2011)

SUBJECT CHEMISTRY

CLASS XI

Time: 3 Hours Max Marks: 70

General Instructions:

All questions are compulsory. Marks for each questions is allotted against it. Answer them according to marks allotted.

Choose the correct option for questions 1 to 5 and give reason/solution for your answer.

1. One mole of calcium phosphide on reaction with excess of water gives(a)one mole of phosphine (PH3). (c) two moles of phosphoric acid (H3PO4).(b)two moles of phosphine (PH3). (d) one mole of phosphorus pentoxide (P2O5).

[1]

2. The set representing the correct order of first ionization potential is:(a) K > Na > Li (c) B > C > N

(b) Be > Mg > Ca (d) Ge > Si > C

[1]

3. Shape and hybridization of IF5 respectively are:(a) trigonal bipyramidal, sp3d (c) square planer, sp3d2(b)see saw, sp3d (d) pentagonal bipyramidal, sp3d3

[1]

4. A reaction cannot take place spontaneously at any temperature when(a)both H and S are positive (c) H is negative and S is positive(b)both H and S are negative (d) H is positive and S is negative

[1]

5. The increasing electron releasing tendencies of Cu, Ag, Fe and Zn are in the order :(a)Ag, Cu, Fe, Zn (c) Zn , Cu, Fe, Ag(b)Cu, Ag, Fe, Zn (d) Fe, Zn , Cu, Ag

[1]

6. How can you explain higher stability of BCl3 as compared to TlCl3? [1]

7. Draw the structure of Cyclohex 2 en 1 ol. [1]

8. What is meant by bond dissociation enthalpy? [1]

9. Draw the cis and trans structures of hex 2 ene. Which isomer will have higher

boiling point?

[2]

10. Give the IUPAC names of the following compounds:

(a)(CH3)2CHCH(NO2)CH=CHCOOH(b)CH3CH2COOCH2CH2Cl

[2]

11. How would you explain the following observations?

(a)LiI is more soluble than KI in ethanol.(b)BaO is soluble but BaSO4 is insoluble in water.

[2]

SET A


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12. What causes the temporary and permanent hardness of water? [2]

13. What is meant by the conjugate acid - base pair? Find the conjugate acid/base for the

following species: HClO4 and HNO2.

[2]

14. Deduce the gas equation pV=nRT from gas laws. Calculate the value of R in joules

K 1 mol 1 .

[2]

15. Write the formal charges of the atoms in nitrite ion. [2]

16. Indicate the number of unpaired electrons in: 24Cr, 14Si, 21Sc and 26Fe. [2]

17. Give one example of a reaction in which dihydrogen acts as a reducing agent and an

oxidizing agent.

[2]

18. 2.5 g of an impure sample of sodium bicarbonate when heated strongly gave 300 mL

of carbon dioxide measured at 270C and 760 mm pressure. Calculate the percentage

purity of the sample.

[2]

19. If the velocity of the electron in the microscope is 1.6 x 10 6 ms 1, calculate de Broglie

wavelength with this electron.

[3]

20. What are the various factors due to which the ionization enthalpy of the main group

elements tends to decreases down a group?

[3]

21. Draw molecular orbital energy level diagram for N2 molecule. [3]

22. 0.64 g of an oxide of sulphur occupies 0.224 L at 2 bar and 273 0C. Identify the oxide

of sulphur.

[3]

23. Calculate the G0 for a reaction; NO (g) +

O2 (g) NO2 (g). Given fH0 at 298 K for

NO (g), NO2 (g) is 90.4 kj mol 1, 33.8 kj mol 1and S0 at 298 K is 70.8 Jk 1 mol 1.

[3]

24. Balance the following equation in basic medium by ion electron method:N2H4 () + ClO3 (aq) NO(g) + Cl (g)

[3]

25. What happens when:

(a)Magnesium is burnt in air?(b)Quick lime is heated with silica?(c)Chlorine reacts with slaked lime?

[3]

26. Show the diagrammatic representation of +R effect by hydroxyl group(-OH) over

benzene ring. Also give reason for its activating effect on benzene towards

electrophilic substitution reactions.

[2,1]

27. What is smog? How is classical smog different from photochemical smog? [1,2]


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28. Write appropriate reason for the following:

(a)Aluminium chloride exists as a dimer.(b)[AlF6] is known but[BF6] is unknown.(c)Boric acid is considered as lewis acid and not a protic acid.(d)Gallium has higher ionization enthalpy than aluminium.(e) Aluminum is electropositive metal but extensively used as structural material.

OR

Write appropriate reason for the following:

(a)SiF6 2 is known butSiCl6 2 is not known.(b)Lead has +2 as more stable oxidation state than +4.(c)Covalency of Silicon is six in its compounds.(d)CO is poisonous in nature.(e) Diamond is used as an abrasive material.

[5]

29. Write short notes on:

(a)Friedal craft reaction (d) Acidity of alkynes.(b)Markownikovs rule. (e) Conformation in alkanes.(c)Wurtz reaction.

OR

(a)Write down the chemical reaction showing the products of ozonolysis of1,2 Dimethyl benzene.

(b)Write down the mechanism to show the formation of chloromethane duringchlorination of methane in the presence of sunlight.

(c) How will you convert benzene into acetophenone.

[5]

[2,2,1]

30. Ethyl acetate is formed by the reaction between ethanol and acetic acid and the

equilibrium is represented as:

CH3COOH () + C2H5OH ( ) CH3COOC2H5() + H2O ()

(a)Write the concentration ratio (reaction quotient), Qc , for this reaction.(note: water is not in excess and is not a solvent in this reaction).

(b)At 293 K, if one starts with 1.00 mol of acetic acid and 0.18 mol of ethanol, there is0.171 mol of ethyl acetate in the final equilibrium mixture. Calculate the equilibrium

constant.

(c)Starting with 0.5 mol of ethanol and 1.0 mol of acetic acid and maintaining it at 293K, 0.214 mol of ethyl acetate is found after sometime. Has equilibrium been reached?

OR

What are the common ion effect and buffer solutions? Explain the buffer action on an

acidic buffer and basic buffer in case of addition of small amount of an acid and base

to it.

[1,2,2]

[1,2,2]

p-1 class xi chemistry 2010-2011

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