#### 12th Standard English Medium Chemistry Reduced Syllabus Two mark Important Questions - 2021(Public Exam )

12th Standard

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Chemistry

Time : 02:00:00 Hrs
Total Marks : 100

Part A

50 x 2 = 100
1. What is the role of Limestone in the extraction of Iron from its oxide Fe2O3?

2. Out of coke and CO, which is better reducing agent for the reduction of ZnO? Why?

3. Name some elements that occur as native elements.

4. What is leaching?

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

6. What is catenation ? describe briefly the catenation property of carbon

7. Write the reaction of diboranes with water and alkali.

8. Give the formula of chlorosilazanes. Explain its preparation from SiCI4.

9. Give the oxidation state of halogen in the following.
a) OF2
b) O2F2
c) Cl2O3
d) I2O4

10. Give two uses of nitric acid

11. How is SO2 an air pollutant?

12. What are inner transition elements?

13. complete the following.
a. MnO42- + H+ ⟶|?
b. C6H5CH3 $\overset { acidified }{ \underset { KMnO_{ 4 } }{ \longrightarrow } }$?
c. MnO4- + Fe2+ ⟶?
d. KMnO4 $\overset { \triangle }{ \underset { Red\quad hot }{ \longrightarrow } }$ ?
e. Cr2O72- + I- + H+ ⟶?
f. Na2Cr2O7 + KCl ⟶?

14. Write ionic equation for the reaction between Cr2O7-2 iODS and Fe2+ ions in acidic medium.

15. Calculate the magnetic moment of Fe3+ ion (Atomic no. of Fe = 26)

16. Many industrial processes use transition metal or their compounds as catalyst. Why?

17. Draw the structure of permanganate ion.

18. Write the formula for the following coordination compounds.
a) potassiumhexacyanidoferrate(II)
b) petacarbonyliron(0)
c) pentaamminenitrito −k−N-cobalt(III)ion
d) hexaamminecobalt(III)sulphate
e) sodiumtetrafluoridodihydroxidochromate(III)

19. Give an example of coordination compound used in medicine and two examples of biologically important coordination compounds

20. Give the names of two complexes which are used in medicines.

21. Write the IUPAC name of [Ag(NH3)2]Cl.

22. Give an example for the complexes possessing co-ordination number 8 and 7

23. Identify the ligand and the central metal in the Co-ordination compound. [Co(NH3)4Cl6]CI

24. Define unit cell

25. Distinguish between hexagonal close packing and cubic close packing.

26. Derive integrated rate law for a zero order reaction A$\longrightarrow$ product

27. Describe the graphical representation of first order reaction.

28. Explain the effect of catalyst on reaction rate with an example

29. Consider the oxidation of nitric oxide to form NO2
2NO(g) + O2(g) ➝2NO (g)
(a). Express the rate of the reaction in terms of changes in the concentration of NO,O2 and NO2.
(b). At a particular instant, when [O2] is decreasing at 0.2 mol L−1s−1 at what rate is [NO2] increasing at that instant?

30. Account for the acidic nature of HClO4. In terms of Bronsted – Lowry theory, identify its conjugate base.

31. The concentration of hydroxide ion in a water sample is found to be 2.5×10-6M. Identify the nature of the solution.

32. Calculate the concentration of OH- in a fruit juice which contains $2\times10^{-3}$ M, H3O+ ion. Identify the nature of the solution.

33. Describe the electrolysis of molten NaCl using inert electrodes

34. Which of 0.1M HCl and 0.1 M KCl do you expect to have greater and why?

35. The resistance of a conductivity cell is measured as 190 Ω using 0.1M KCl solution (specific conductance of 0.1M KCl is 1.3 Sm-1) . When the same cell is filled with 0.003 M sodium chloride solution, the measured resistance is 6.3KΩ. Both these measurements are made at a particular temperature. Calculate the specific and molar conductance of NaCl solution. Given that

36. In case of chemisorption, why adsorption first increases and then decreases with temperature?

37. The mechanism of Fridel crafts reaction is given below
${ C }_{ 6 }{ H }_{ 5 }+{ { CH }_{ 3 }Cl\overset { anhydrous\\ \quad \quad \quad { Alcl }_{ 3 } }{ \longrightarrow } }{ C }_{ 6 }{ H }_{ 5 }{ CH }_{ 3 }+HCl$

38. Formation of water due to the reaction of H2 and O2 in the presence of Cu can be given as

39. What is the major product obtained when two moles of ethyl magnesium bromide is treated with methyl benzoate followed by acid hydrolysis.

40. Can we use nucelophiles such as NH3,CH3- for the Nucleophilic substitution of alcohols

41. Identify X and Y.
${ CH }_{ 3 }CO{ CH }_{ 2 }{ CH }_{ 2 }COO{ C }_{ 2 }{ H }_{ 5 }\overset { { CH }_{ 3 }MgBr }{ \longrightarrow } X\overset { { H }_{ 3 }{ O }^{ + } }{ \longrightarrow } Y$

42. What is angle of deviation due to reflection?

43. Write down the possible isomers of the C4H9NO2 give their IUPAC names

44. What happens when
i. 2 – Nitropropane boiled with HCl
ii. Nitrobenezenelectrolytic reduction in strongly acidic medium.
iii. Oxidation of tert – butylamine with KMnO4
iv. Oxidation of acetoneoxime with trifluoroperoxy acetic acid.

45. Identify compounds A,B and C in the following sequence of reactions.
i) ${ C }_{ 6 }{ H }_{ 5 }NO_{ 2 }\overset { Fe/HCL }{ \longrightarrow } A\overset { HN{ O }_{ 2 } }{ \underset { 273K }{ \longrightarrow } } B\overset { { C }_{ 6 }{ H }_{ 5 }OH }{ \longrightarrow } C$
ii) ${ C }_{ 6 }{ H }_{ 5 }N_{ 2 }cl\overset { CuCN }{ \longrightarrow } A\overset { H_{ 2 }O/H^{ + } }{ \longrightarrow } B\overset { NH_3 }{ \longrightarrow } C$

iii) ${ C }{ H }_{ 3 }{ C }{ H }_{ 2 }I\overset { NaCN}{ \longrightarrow } A\overset {OH^-}{ \underset {Partial hydrolysis}{ \longrightarrow } } B\overset {NaOH+Br_2 }{ \longrightarrow } C$
iv) ${ C }{ H }_{ 3 }NH_{ 2 }\overset { CH_3 Br }{ \longrightarrow } A\overset { CH_{ 3 }COCl}{ \longrightarrow } B\overset { B_2H_6 }{ \longrightarrow } C$
v) ${ C }_{ 6 }{ H }_{ 5 }NH_{ 2 }\overset { (CH_{ 3 }CO)_{ 2 }O }{ \underset { Pyridine }{ \longrightarrow } } A\overset { HNO_{ 3 } }{ \underset { H_{ 2 }SO_{ 4 },288K }{ \longrightarrow } } B\overset { { H }_{ 2 }O/{ H }^{ + } }{ \longrightarrow C }$
vi)

vii) ${ C }{ H }_{ 3 }CN_{ 2 }NC\overset { HgO }{ \longrightarrow } A\overset { H_{ 2 }O }{ \longrightarrow } B\overset { i)\quad NaN{ O }_{ 2 }/HCL }{ \underset { ii){ \quad H }_{ 2 }O }{ \longrightarrow } }$

46. Name the Vitamins whose deficiency cause
i) rickets
ii) scurvy

47. Write a short note on peptide bond

48. Which chemical is responsible for the antiseptic properties of dettol.

49. Name one substance which can act as both analgesic and antiphyretic

50. What are food preservatives?