#### Quarterly Model Question Paper

12th Standard EM

Reg.No. :
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Chemistry

Time : 02:45:00 Hrs
Total Marks : 70
15 x 1 = 15
1. Bauxite has the composition

(a)

Al2O3

(b)

Al2O3nH2O

(c)

Fe2O3.2H2O

(d)

None of these

2. Cupellation is a process used for the refining of

(a)

Silver

(b)

(c)

Copper

(d)

iron

3. Boric acid is an acid because its molecule (NEET)

(a)

contains replaceable H+ ion

(b)

gives up a proton

(c)

combines with proton to form water molecule

(d)

accepts OH- from water ,releasing proton.

4. The molarity of given orthophosphoric acid solution is 2M. its normality is

(a)

6N

(b)

4N

(c)

2N

(d)

none of these

5. The alloy of copper that contain Zinc is

(a)

Monel metal

(b)

Bronze

(c)

bell metal

(d)

brass

6. Coinage metals are _________

(a)

normal metals

(b)

transition metals

(c)

active metals

(d)

alkali metals

7. An excess of silver nitrate is added to 100ml of a 0.01M solution of pentaaquachloridochromium(III)chloride. The number of moles of AgCl precipitated would be

(a)

0.02

(b)

0.002

(c)

0.01

(d)

0.2

8. ______________ valencies are directional in nature.

(a)

primary

(b)

secondary

(c)

teriary

(d)

None

9. The composition of a sample of wurtzite is FeO0.931.00 what % of Iron present in the form of Fe3+?

(a)

16.05%

(b)

15.05%

(c)

18.05%

(d)

17.05%

10. The crystal with a metal deficiency defect is

(a)

NaCl

(b)

FeO

(c)

ZnO

(d)

KCl

11. Which type of defect is found in transition metals that have variable valency?

(a)

Frenkel defect

(b)

Schottky defect

(c)

Line defect

(d)

Metal deficiency defect

12. The total number of atoms per unit cell in fee lattice is__________.

(a)

4

(b)

8

(c)

12

(d)

2

13. The addition of a catalyst during a chemical reaction alters which of the following quantities? (NEET)

(a)

Enthalpy

(b)

Activation energy

(c)

Entropy

(d)

Internal energy

14. For a reaction: aA ⟶ bB, the rate of reaction is doubled when the concentration of A is increased by four times. The rate of reaction is equal to

(a)

k[A]a

(b)

$k{ \left[ A \right] }^{ \frac { 1 }{ 2 } }$

(c)

$k{ \left[ A \right] }^{ \frac { 1 }{ a } }$

(d)

K[A]

15. Activation energy of a reactant is reduced by ___________________

(a)

increased temperature

(b)

reduced temperature

(c)

increased pressure

(d)

reduced pressure

16. 6 x 2 = 12
17. What is the role of Limestone in the extraction of Iron from its oxide Fe2O3?

18. Which type of ores can be concentrated by froth floatation method? Give two examples for such ores.

19. Name the various refming process

20. How is nitrogen prepared from liquid air?

21. Arrange the following complex ions in the increasing order of crystal filed splitting energy (${ \triangle }_{ 0 }$) [CrCI6]3-, [Cr(CN)6]3-, [Cr(NH3)6]3+

22. What are point defects?

23. 6 x 3 = 18
24. Explain the following terms with suitable examples.
(i) Gangue
(ii) slag

25. Distinguish Roasting and Calcination

26. List the applications of gold

27. Give the uses of silicones

28. Write the reason for the anamolous behaviour of Nitrogen.

29. What is chromyl chloride test? Give equations.

30. 5 x 5 = 25
31. Write a note on zeolites.

32. Mention the type of hybridisation and magnetic property of the following complexes using VB theory a) [FeF6]4- b) [Fe(CN)6]4-

33. Give the structure for the following compounds.
(i) pentaamminechlorocobalt (III) ion
(ii) Triamminetrinitrito- k N cobalt (III)
(ill) tetraammineaquabromidooobalt(III)nitrate
(iv) Dichloridobisethane-1 )2-diamine) cobalt (lIl) chloride
(v) Tetraamminecopper (lI)sulphate

34. From the following data, show that the decomposition of hydrogen peroxide is a reaction of the first order:

 t(min) 0 10 20 V(ml) 46.1 29.8 19.3

Where t is the time in minutes and V is the volume of standard KMnO4 solution required for titrating the same volume of the reaction mixture.

35. The specific reaction. rates of a chemical reaction are 2.45 x 10-5 sec-1 at 273 K and 16.2 x10-4 sec-1 at 303 K. Calculate the activation energy.