12th Standard English Medium Chemistry Reduced Syllabus Annual Exam Model Question Paper with Answer key - 2021

12th Standard

Reg.No. :
•
•
•
•
•
•

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. Helium is used in balloons in the place of, hydrogen because it is________

(a)

incombustible

(b)

(c)

lighter than hydrogen

(d)

both (a) and(c)

4. Which one of the following is not correct?

(a)

La(OH)2 is less basic than Lu(OH)3

(b)

In lanthanoid series ionic radius of Ln3+ ions decreases

(c)

La is actually an element of transition metal series rather than lanthanide series

(d)

Atomic radii of Zr and Hf are same because of lanthanide contract

5. Which one of the following complexes is not expected to exhibit isomerism?

(a)

[Ni(NH3)4(H2O)2]2+

(b)

<>

(c)

[Co(NH3)5SO4]Cl

(d)

[Fe(en)3]3+

6. Which one of the following statements is wrong about Frenkel defect?

(a)

An ion occupies an interstitial position

(b)

Anion is much larger in size than the cation

(c)

The crystal remains neutral

(d)

Non-stoichiometric compound is formed

7. Assertion: rate of reaction doubles when the concentration of the reactant is doubles if it is a first order reaction.
Reason: rate constant also doubles
Codes:
(a) Both assertion and reason are true and reason is the correct explanation of assertion.
(b) Both assertion and reason are true but reason is not the correct explanation of assertion.
(c) Assertion is true but reason is false
(d) Both assertion and reason are false.

(a)

Both assertion and reason are true and reason is the correct explanation of assertion.

(b)

Both assertion and reason are true but reason is not the correct explanation of assertion.

(c)

Assertion is true but reason is false

(d)

Both assertion and reason are false.

8. The percentage of pyridine (C5H5N) that forms pyridinium ion (C5H5NH) in a 0.10M aqueous pyridine solution (Kb for C5H5N= 1.7×10-9) is

(a)

0.006%

(b)

0.013%

(c)

0.77%

(d)

1.6%

9. Ostwald's dilution law is applicable in the case of the solution of

(a)

CH3COOH

(b)

NaCI

(c)

NaOH

(d)

H2SO4

10. Debye constants A and B depend on _____________

(a)

nature of the solvent

(b)

temperature

(c)

concentration of the solvent

(d)

both nature of the solvent and temperature

11. Match the following

 a V2O5 i High density polyethylene b Ziegler – Natta ii PAN c Peroxide iii NH3 d Finely divided Fe iv H2SO4
(a)
 A B C D iv i ii iii
(b)
 A B C D i ii iv iii
(c)
 A B C D ii iii iv i
(d)
 A B C D iii iv ii i
12. In the sequence of reactions Identify 'C'.

(a)

(b)

(c)

(d)

13. Predict the product Z in the following series of reactions Ethanoic acid $\overset { { PCI }_{ 5 } }{ \longrightarrow } X\overset { { C }_{ 6 }{ H }_{ 6 } }{ \underset { Anhydrous \ AlcI }-_{3}{ \longrightarrow } } Y\overset { 1){ CH }_{ 3 }MgBr }{ \underset { II){ H }_{ 3 }{ O }^{ + } }{ \longrightarrow } } Z.$

(a)

(CH3)2 C(OH)C6H5

(b)

CH3CH(OH)C6H5

(c)

CH3CH(OH)CH2- CH3

(d)

14. Electrolytic reduction of nitrobenzene in strongly acidic medium gives

(a)

aniline

(b)

p - aminophenol

(c)

m-nitroaniline

(d)

azoxybenzene

15. Which contains a long chain ester?

(a)

Wax

(b)

Cooking oil

(c)

Turpentine oil

(d)

Cellulose

16. Part II

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

6 x 2 = 12
17. Name the metals that are obtained from their oxides using hydrogen as reducing agent.

18. Give the structure of CO and CO2.

19. What is the reaction of Phosphorous with alkali?

20. Name the type of isomerism that occurs in complexes in which both cation and anion are complex ions.

21. Define unit cell

22. How does the value of rate constant vary with reactant constant.

23. Calculate the pH of 0.001M HCl solution

24. Give a mathematical expression that relates I cell constant, specific conductance and specific resistance.

25. Suggest a suitable reagent to prepare secondary alcohol with identical group using Grignard reagent.

26. Part III

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

6 x 3 = 18
27. List the applications of gold

28. Which is the last element in the series of the actinoids? Write the electronic configuration of this element comment on the possible oxidation state of this element.

29. Why does the emf of Leclanche cell decrease?

30. Addition of Alum purifies water. Why?

31. How will you prepare phenol (i) From chloro benzene (ii) From benzene sulphonic acid?

32. Identify A, B,C and D
$\text { ethanoic acid } \stackrel{\mathrm{SOCl}_{2}}{\longrightarrow} \mathrm{A} \stackrel{\mathrm{Pd} / \mathrm{BaSO}_{4}}{\longrightarrow} \mathrm{B} \stackrel{\mathrm{NaOH}}{\longrightarrow} \mathrm{C} \stackrel{\longrightarrow}{\triangle} \mathrm{D}$

33. How are the following compounds obtained from benzene diazonium chloride?
(i) phenol
(ii) ester
(iii) p-hydroxy azo benzene

34. Give the structure of α - D - glucose and β- D - glucose

36. Part IV

5 x 5 = 25
1. A double salt which contains fourth period alkali metal (A) on heating at 500K gives (B). aqueous solution of (B) gives white precipitate with BaCl2 and gives a red colour compound with alizarin. Identify A and B.

2. Give reason for the following :
(i) N2O5 is more acidic than N2O3
(ii) Thermal stability decreases from H2O to H2Te.
(iii) Fluoride ion has higher hydration enthalpy than chloride ion.

1. Complete the following reactions
(i) Cr2O72-
(ii) Cr2O7- + 6I-+ 14H+ ⟶
(iii)  Cr2O7- + 3S2-+ 14H+ ⟶
(iv) Cr2O7- + 3SO2+ 14H+
(v) Cr2O7- +3Sn2+ + 14H+ ⟶
(vi) K2Cr2O7 + 8H2SO4 + 3CH3CH2OH ⟶
(vii) 2MnO4- + 5(COO)2- + 6H+ ⟶
(viii) 2MnO4- + 10I+ 16H+
(ix) 2MnO4- + 5S2-+ 16H+ ⟶
(x) 2MnO4- + 5NO2- + 6H+ ⟶
(xi) 2KMnO4 + 3H2SO4 + 5CH3CH2OH ⟶
(xii) 2MnO4- + 5SO32- + 6H+

2. Ionic solids, which have anionic vacancies due to metal excess defect, develop colour. Explain with the help of a suitable example.

1. How are metal carbonyls classified depending on the number of metal atoms?

2. Benzene diazonium chloride in aqueous solution decomposes according to the quation ${ C }_{ 6 }{ H }_{ 5 }{ N }_{ 2 }Cl\longrightarrow { C }_{ 6 }{ H }_{ 5 }Cl+{ N }_{ 2 }$ Starting with an initial concentration of 101 g L-1, the volume of N2 gas obtained at 50 °C at different intervals of time was found to be as under:

 t(min) 6 12 18 24 30 $\infty$ Vol.of N2 (ml) 19.3 32.6 41.3 46.5 50.4 58.3

Show that the above reaction follows the first order kinetics. What is the value of the rate constant?

1. Write the expression for the solubility product of Ca3 (PO4)2

2. 0.44g of a monohydric alcohol when added to methyl magnesium iodide in ether liberates at STP 112 cm3 of methane with PCC the same alcohol form a carbonyl compound that answers silver mirror test. Identify the compound.

1. Write the characteristics of adsorption.

2. Account for reducing nature of formic acid.