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#### Public Model Question Paper Part-VIII 2019 - 2020

12th Standard EM

Reg.No. :
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Chemistry

Time : 02:45:00 Hrs
Total Marks : 70

Part I

Choose the most suitable answer from the given four alternatives and write the option code with the corresponding answer.

15 x 1 = 15
1. In Hall-Herold process___________act as an, anode.

(a)

Carbon blocks

(b)

hydrogen

(c)

copper rods

(d)

Zinc rods

2. The compound that is used in nuclear reactors as protective shields and control rods is

(a)

Metal borides

(b)

metal oxides

(c)

Metal carbonates d) metal carbide

(d)

none of these

3. The incorrect statement among the following is_________

(a)

Reducing character of hydrides of group 15 increases down the group

(b)

Basicity of hydrides of group 15 increases down the group

(c)

NCl5 does not exist

(d)

Phosphorus and arsenic can form P$\pi$-drt bond but not nitrogen

4. Which one of the following statements related to lanthanons is incorrect?

(a)

Europium shows +2 oxidation state

(b)

The basicity decreases as the ionic radius decreases from Pr to Lu.

(c)

All the lanthanons are much more reactive than aluminium

(d)

Ce4+ solutions are widely used as oxidising agents in volumetric analysis.

5. Which one of the following pairs represents linkage isomers?

(a)

[Cu(NH3)4][ptCl4] and [pt(NH3)4][CuCl4]

(b)

[Co(NH3)5(NO3)]SO4 and [Co(NH3)5(ONO)]

(c)

[Co(NH3)4(NCS)2]ct and [Co(NH3)4(SCN)2]Cl

(d)

both (b) and (c)

6. The number of carbon atoms per unit cell of diamond unit cell is_________

(a)

8

(b)

6

(c)

1

(d)

4

7. After 2 hours, a radioactive substance becomes $\left( \cfrac { 1 }{ 16 } \right) ^{ th }$ of original amount Then the half life ( in min) is

(a)

60 minutes

(b)

120 minutes

(c)

30 minutes

(d)

15 minutes

8. If the solubility product of lead iodide is 3.2 ×10-8 , its solubility will be

(a)

2×10-3M

(b)

4×10-4M

(c)

1.6 ×10-5M

(d)

1.8 ×10-5M

9. Conjugate acid of hydride ion is ________

(a)

hydronium ion

(b)

hydroxide ion

(c)

hydrogen

(d)

water

10. Low molar conductivity at high concentration is due to _____________

(a)

High attractive force between oppositively charged ions

(b)

Viscous drag due to greater solvation

(c)

Both High attractive force between oppositively charged ions and Viscous drag due to greater solvation

(d)

Neither High attractive force between oppositively charged ions and Viscous drag due to greater solvation

11. Which one of the following is an example for homogeneous catalysis?

(a)

manufacture of ammonia by Haber’s process

(b)

manufacture of sulphuric acid by contact process

(c)

hydrogenation of oil

(d)

Hydrolysis of sucrose in presence of all HCl

12. The test used to distinguish wish 10, 20 and 30 alcohol is ________

(a)

Lucas test

(b)

Victor Meyer's

(c)

dehydrogenation

(d)

all the above

13. (a)

(b)

(c)

(d)

14. CH3-CH2-CH2-CH2NO2 and ${ CH }_{ 3 }-\underset { \overset { | }{ { CH }_{ 3 } } }{ CH } -{ CH }_{ 2 }-{ NO }_{ 2 }$ exhibits _________ isomerism

(a)

chain

(b)

position

(c)

functional

(d)

optical

15. Cholesterol is an example of_________

(a)

protein

(b)

vitamin

(c)

carbohydrat

(d)

lipid

16. Part II

Answer any 6 questions. Question no. 24 is compulsory.

6 x 2 = 12
17. Write the two similarities between calcination and roasting.

18. Describe briefly allotropism in p- block elements with specific reference to carbon

19. Give two uses of nitrogen

20. What is hydrate isomerism? Give an example.

21. What are point defects?

22. The decomposition reaction of ammonia gas on platinum surface has a rate constant R = 2.5 X 10-4mol L-1. What is the order of the reaction.

23. Calculate the pH of 0.04 M HNO3 Solution.

24. What are primary cells?

25. Predict the major product, when 2-methyl but -2-ene is converted into an alcohol in each of the following methods.
(i) Acid catalysed hydration
(ii) Hydroboration
(iii) Hydroxylation using bayers reagent

26. Part III

Answer any 6 questions. Question no. 33 is compulsory.

6 x 3 = 18
27. Define the term slag.

28. Write the properties of interstitial compound.

29. What is the oxidation and reduction half cell in a Daniel cell?

30. What happens when a colloidal sol of Fe(OH)3 and AS2O3 are mixed?

31. Halo alkane are easily prepared from alcohols while aryl halides cannot be prepared from phenol.- Justify.

32. An alkene (A) on ozonolysis gives propanone and aldehyde (B). When (B) is oxidised (C) is obtained. (C) is treated with BriP gives (D) which on hydrolysis gives (E). When propanone is treated with HCN followed by hydrolysis gives (E). Identify A) B) C) D and E.

33. Write a note on the basicity of amines

34. What is starch? What are the ultimate hydrolysis products?

35. Identify the polymer and write the reaction involved.
(i) Buta-1,3-diene and styrene in the presence of sodium.
(ii) 3 - hydroxy butanoic acid and 3-hydroxy pentanoic acid.

36. Part IV

5 x 5 = 25
1. Complete the following reactions

ii) $C_6H_5-CHCH(OH)CH(CH_3)_2 \overset{ConH_2SO_4}\longrightarrow$

2. Give two tests for aldehydes.

1. Establish a relationship between the solubility product and molar solubility for the following
a) BaSO b)Ag2(CrO4)

2. Write any five applications of colloids in day - to day life.

1. A cubic solid 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? What is the coordination numbers of P and Q?

2. How do nature of the reactant influence rate of reaction.

1. Write a short note on the oxidation states of 3d series elements.

2. How are metal carbonyls classified based on the structure?

1. A hydride of 2nd period alkali metal (A) on reaction with compound of Boron (B) to give a reducing agent (C). identify A , B and C.

2. What are the properties of inter halogen compounds?