#### Half Yearly Model Question Paper 1

11th Standard

Reg.No. :
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Chemistry

Do not write anything on question paper.

Time : 02:30:00 Hrs
Total Marks : 70

Part A

15 x 1 = 15
1. Hot concentrated sulphuric acid is a moderately strong oxidizing agent. Which of the following reactions does not show oxidising behaviour?

(a)

Cu + 2H2 SO4 $\longrightarrow$ CuSO4 +SO2 + 2H2O

(b)

C + 2H2 + SO4 $\longrightarrow$ CO2 + 2SO2 + 2H2O

(c)

BaCl2 + H2SO4 $\longrightarrow$ BaSO4 + 2HCl

(d)

None of the above

2. Which of the following pairs of d-orbitals will have electron density along the axes ?

(a)

dz2, dxz

(b)

dxz, dyZ

(c)

dz2, dx2-y2

(d)

dxy ,dx2-y2

3. The value of Bohr radius for hydrogen atom is

(a)

0.529 $\times$ 10-8 cm

(b)

0.529 $\times$ 10-10 cm

(c)

0.529 $\times$ 10-12 cm

(d)

0.529 $\times$ 10-12 cm

4. In which of the following options the order of arrangement does not agree with the variation of property indicated against it?

(a)

I< Br < CI < F (increasing electron gain enthalpy)

(b)

Li < Na < K < Rb (increasing metallic radius)

(c)

Al3+< Mg2+ < Na+ - (increasing ionic size)

(d)

B < C < O < N (increasing first ionisation enthalpy)

5. The highest ionization energy is exhibited by_________

(a)

halogens

(b)

alkaline earth metals

(c)

transition metals

(d)

noble gases

6. Zeolite used to soften hardness of water is hydrated

(a)

Sodium aluminium silicate

(b)

Calcium aluminium silicate

(c)

Zinc aluminium borate

(d)

Lithium aluminium hydride

7. Among the following the least thermally stable is

(a)

K2CO3

(b)

Na2CO3

(c)

BaCO3

(d)

Li2CO3

8. Which of the following is the correct expression for the equation of state of van der Waals gas?

(a)

$\left( P+\frac { a }{ { n }^{ 2 }{ V }^{ 2 } } \right) (V-nb)=nRT$

(b)

$\left( P+\frac { na }{ { n }^{ 2 }{ V }^{ 2 } } \right) (V-nb)=nRT$

(c)

$\left( P+\frac { { an }^{ 2 } }{ { V }^{ 2 } } \right) (V-nb)=nRT$

(d)

$\left( \frac { P+{ n }^{ 2 }{ a }^{ 2 } }{ { V }^{ 2 } } \right) (V-ab)=nRT$

9. The amount of heat exchanged with surrounding at constant temperature pressure is given by the quantity

(a)

ΔE

(b)

ΔH

(c)

ΔS

(d)

ΔG

10. Two similar reactions are given below:
H2(g)+$\frac { 1 }{ 2 }$O2(g) $\rightarrow$H2O(g); $\Delta$H = $\Delta$H1
H2(g)+$\frac { 1 }{ 2 }$O2(g)$\rightarrow$H2O(l); $\Delta$H =  $\Delta$H2
In terms of magnitude, of $\Delta$H

(a)

$\Delta$H1 > $\Delta$H2

(b)

$\Delta$H1 < $\Delta$H2

(c)

$\Delta$H1 = $\Delta$H2

(d)

cannot be predicted

11. Solubility of carbon dioxide gas in cold water can be increased by

(a)

increase in pressure

(b)

decrease in pressure

(c)

increase in volume

(d)

none of these

12. For the formation of Two moles of SO3(g) from SO2 and O2, the equilibrium constant is K1. The equilibrium constant for the dissociation of one mole of SO3 into SO2 and O2 is

(a)

$1/K_1$

(b)

$K_1^2$

(c)

$({1\over K_1})^{1/2}$

(d)

${K_1\over 2}$

13. At 100C the vapour pressure of a solution containing 6.5g a solute in 100g water is 732mm. If Kb = 0.52, the boiling point of this solution will be

(a)

102oC

(b)

100oC

(c)

101oC

(d)

100.52oC

14. Structure of the compound whose IUPAC name is 5,6 - dimethylhept - 2 - ene is

(a)

(b)

(c)

(d)

None of these

15. An alkyl bromide (A) reacts with sodium in ether to form 4, 5– diethyloctane, the compound (A) is

(a)

CH3 (CH2)3 Br

(b)

CH3(CH2)5 Br

(c)

CH3(CH2)3 CH(Br)CH3

(d)

${ CH }_{ 3 }-{ \left( { CH }_{ 2 } \right) }_{ 3 }-CH\left( Br \right) -\underset { \overset { { | } }{ { CH }_{ 3 } } }{ { CH }_{ 3 } }$

16. Part B

Answer any six in which question no. 24 is compulsory.

6 x 2 = 12
17. How many orbitals are possible for n =4?

18. Discuss the three types of Covalent hydrides.

19. State charles law and give an example.

20. At 0°C, ice and water are in equilibrium and the enthalpy change for the process, H2O(s) $\rightleftharpoons$ H2O(l) is 6 KJ mol-1 Calculate the entropy change for the conversion ice into water.

21. What the relation between KP and KC. Give one example for which KP is equal to KC.

22. Write a note on homologous series.

23. Explain inductive effect with suitable example.

24. Describe the mechanism of Nitration of benzene.

25. Which alkyl halide from the following pair is i) chiral ii) undergoes faster SN2 reaction?

26. Part C

Answer any six in which question no. 33 is compulsory.

6 x 3 = 18
27. What mass of N2 will be required to produce 34g of NH3 by the reaction, N2 + 3H2 $\longrightarrow$ 2NH3·

28. Determine the values of all the four quantum numbers of the 8th electron in O- atom and 15th electron in CI atom and the last electron in chromium.

29. Give a brief account of the shapes of atomic orbitals?

30. The second electron affinity of O is positive, whereas first is negative. Give reason.

31. Would it be easier to drink water with a straw on the top of Mount Everest?

32. For the reaction,
A2(g) + B2(g) ⇌ 2AB(g) ; ΔH is –ve.
the following molecular scenes represent different reaction mixture (A – green, B – blue)

i) Calculate the equilibrium constant KP and (KC).
ii) For the reaction mixture represented by scene (x), (y) the reaction proceed in which directions?
iii) What is the effect of increase in pressure for the mixture at equilibrium.

33. What volume of 4M HCl and 2M HCl should be mixed to get 500 mL of 2.5 M HCl?

34. Write structural formula for the following compounds
(i) m - dinitrobenzene
(ii) p-dichloro benzene
(iii)1, 3, 5- Trimethyl benzene.

35. An organic compound (A) with molecular formula C2H5Cl reacts with KOH gives compounds (B) and with alcoholic KOH gives compound (C). Identify (A),(B), and (C)

36. Part D

5 x 5 = 25
1. Calculate the energy required for the process.
${ He }_{ (g) }^{ + }\longrightarrow { He }_{ (g) }^{ 3+ }+{ e }^{ - }$
The ionisation energy for the H atom in its ground state is -13..6 ev atom-1

2. What is screening effect? Briefly give the basis for pauling's scale of electronegativity.

1. List out and compare the chemical properties of metals and non-metals.

2. Compare the structures of H2O and H2O2 .

1. A 10 L cylinder consist of mixture of helium, oxygen, and nitrogen of masses 0.4 g, 1.6 g and 1.4 g at 27°C. Calculate the partial pressures of He, O and N and finally arrive at the total pressure. Assume the gases to behave ideally.

2. Write down the Born-Haber cycle for the formation of CaCl2

1. The atmospheric oxidation of NO
2NO(g) + O2(g) ⇌ 2NO2(g)
was studied with initial pressure of 1 atm of NO and 1 atm of O2. At equilibrium, partial pressure of oxygen is 0.52 atm calculate Kp of the reaction.

2. A sample of 12 M Concentrated hydrochloric acid has a density 1.2 gL–1 Calculate the molality

1. Give the IUPAC names of the following compounds.
(i) (CH3)2CH – CH2 – CH(CH3) – CH(CH3)2
(ii) ${ CH }_{ 3 }-\underset { \overset { | }{ { CH }_{ 3 } } }{ CH } -\underset { \overset { | }{ Br } }{ CH } -{ CH }_{ 3 }$
(iii) CH3 - O - CH3
(iv) ${ CH }_{ 2 }-{ CH }_{ 2 }-\underset { \overset { | }{ OH } }{ CH } -CHO$
(v) CH2 = CH - CH = CH2
(vi) ${ CH }_{ 3 }-C\equiv C-\underset { \overset { | }{ Cl } }{ CH } -{ CH }_{ 3 }$
(vii)
(viii)
(ix)
(x)
(xi)
(xii)
(xiii)
(xiv)
(xv)

2. Give IUPAC names for the following compounds
1) CH3 – CH = CH – CH = CH – C ≡ C – CH3
2)
3) (CH3)3 C – C ≡ C – CH (CH3)2
4) ethyl isopropyl acetylene
5) CH ≡ C – C ≡ C – C ≡ CH