#### 12th Standard Chemistry English Medium Reduced Syllabus Model Question paper With Answer Key -2021 Part - 2

12th Standard

Reg.No. :
•
•
•
•
•
•

Chemistry

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

Part I

Answer all the questions.

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

15 x 1 = 15
1. The metal oxide which cannot be reduced to metal by carbon is

(a)

PbO

(b)

AL2O3

(c)

ZnO

(d)

Feo

2. Which of the following is used for concentrating ore in metallurgy?

(a)

Leaching

(b)

Roasting

(c)

Froth floatation

(d)

Both (a) and (c)

3. The geometry at which carbon atom in diamond are bonded to each other is

(a)

Tetrahedral

(b)

graphene

(c)

Fullerene

(d)

dry ice

4. Among the following, which is the strongest oxidizing agent?

(a)

Cl2

(b)

F2

(c)

Br2

(d)

l2

5. The magnetic moment of Mn2+ ion is

(a)

5.92BM

(b)

2.80BM

(c)

8.95BM

(d)

3.90BM

6. 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.

7. As per IUPAC guidelines, the name of the complex [Co(en)2(ONO)Cl]Cl is

(a)

chlorobisethylenediaminenitritocobalt(III) chloride

(b)

chloridobis(ethane-1,2-diamine)nitro  K-Ocobaltate(III) chloride

(c)

chloridobis(ethane-1,2-diammine)nitrito K-Ocobalt(II) chloridde

(d)

chloridobis(ethane-1,2-diamine)nitro K-Ocobalt(III) chloride

8. Choose the correct statement

(a)

Square planar complexes are more stable than octahedral complexes

(b)

The spin only magnetic moment of [Cu(Cl)4]2- is BM and it has square planar structure.

(c)

Crystal field splitting energy $\left( { \Delta }_{ 0 } \right)$ [FeF6]4- is higher than the $(\Delta _{ 0 })$ $[Fe(CN)6]{ { 4 }^{ - } }$

(d)

crystal field stabilization energy of [V(H2O)6]2+ is higher than the crystal field stabilization of [Ti(H2O)6]2+

9.  if ‘a’ stands for the edge length of the cubic system ; sc , bcc, and fcc. Then the ratio of radii of spheres in these systems will be respectively

(a)

$\left( \cfrac { 1 }{ 2 } a;\cfrac { \sqrt { 3 } }{ 2 } a;\cfrac { \sqrt { 2 } }{ 2 } a \right)$

(b)

$\left( \sqrt { 1a } :\sqrt { 3a } :\sqrt { 2a } \right)$

(c)

$\left( \cfrac { 1 }{ 2 } a:\cfrac { \sqrt { 3 } }{ 4 } a:\cfrac { 1 }{ 2\sqrt { 2 } } a \right)$

(d)

$\cfrac { 1 }{ 2 } a:\sqrt { 3 } a:\cfrac { 1 }{ \sqrt { 2 } } a$

10. The correct difference between first and second order reactions is that (NEET)

(a)

A first order reaction can be catalysed; a second order reaction cannot be catalysed.

(b)

The half life of a first order reaction does not depend on [A0]; the half life of a second order reaction does depend on [A0].

(c)

The rate of a first order reaction does not depend on reactant concentrations; the rate of a second order reaction does depend on reactant concentrations.

(d)

The rate of a first order reaction does depend on reactant concentrations; the rate of a second order reaction does not depend on reactant concentrations.

11. Statement :
To stop bleeding from an injury, ferric chloride can be applied. Which comment about the statement is justified?

(a)

It is not true, ferric chloride is a poison.

(b)

It is true, Fe3+ ions coagulate blood which is a negatively charged sol

(c)

It is not true; ferric chloride is ionic and gets into the blood stream.

(d)

It is true, coagulation takes place because of formation of negatively charged sol with Cl-.

12. Assertion : Phenol is more reactive than benzene towards electrophilic substitution reaction
Reason : In the case of phenol, the intermediate arenium ion is more stabilized by resonance
Codes:
(a) if both assertion and reason are true and reason is the correct explanation of assertion.
(b) if 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)

if both assertion and reason are true and reason is the correct explanation of assertion.

(b)

if 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.

13. Which one of the following reduces tollens reagent

(a)

formic acid

(b)

acetic acid

(c)

benzophenone

(d)

none of these

14. CH3CH2 Br $\overset { aqNaOH }{ \underset { \Delta }{ \longrightarrow } } A\overset { { KMnO }_{ 4 }{ /H }^{ + } }{ \underset { \Delta }{ \longrightarrow } } B\overset { { NH }_{ 3 } }{ \underset { \Delta }{ \longrightarrow } } C\overset { { Br }_{ 2 }/NaOH }{ \longrightarrow } D \ D'is$

(a)

bromomethane

(b)

$\alpha$-bromo sodium acetate

(c)

methanamine

(d)

acetamide

15. Among the following, the reaction that proceeds through an electrophilic substitution, is :

(a)

(b)

(c)

(d)

1. Part II

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

9 x 2 = 18
16. What is passivation?

17. What are limitations of Freundlich adsorption isotherm?

18. ${ C }_{ 6 }{ H }_{ 5 }{ NH }_{ 2 }\xrightarrow [ 273k,HCl ]{ { HNO }_{ 2 } } A\xrightarrow [ { Cu }_{ 2 }({ CN })_{ 2 } ]{ KCN } B\underrightarrow { { H }_{ 3 }O } C$
Identify A, Band C.

19. Aniline reacts with bromine water to give a white precipitate.
(i) Give the chemical formula of the white precipitate formed in the above reaction.
(ii) Write the chemical reaction involved

20. Identify whether the following compounds are D or L isomers.

21. What are epimers?

22. A child is diagnosed with bleeding gums, is likely to have the deficiency of which vitamin?

23. Name the substance used as an antiseptic as well as disinfectant.

24. Explain the action of morphine as a pain killer.

1. Part III

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

9 x 3 = 27
25. Give one example for each of the following
(i) icosogens
(ii) tetragen
(iii) prictogen
(iv) chalcogen

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

27. Identify the order for the following reactions
(i) Rusting of Iron
(ii) Radioactive disintegration of 92U238
(iii) $2A+3B\longrightarrow products$;rate k[A]1/2[B]2

28. Why is AC current used instead of DC in measuring the electrolytic conductance?

29. Derive the relation between EMF and free energy.

30. Account for the following:
(a) Lower members of alcohols are soluble in water but higher members are not.
(b) Alcohols cannot be used as solvent for Grignard reagent.

31. What is the action of HCN on
(i) propanone
(ii) 2,4-dichlorobenzaldehyde.
(iii) ethanal

32. Write a note on
(i) Perkin's reaction, and
(ii) Knoevenagal reaction.

33. Distinguish between fat soluble and water soluble vitamins.

1. Part IV

Answer all the questions.

10 x 5 = 50
34. The selection of reducing agent depends on the thermodynamic factor: Explain with an example.

35. List the applications of iron

36. Deduce the oxidation number of oxygen in hypofluorous acid – HOF.

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

38. The time for half change in a first order decomposition of a substance A is 60 seconds. Calculate the rate constant. How much of A will be left after 180 seconds?

39. 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.

40. Write a note on sacrificial protection.

41. Write all possible isomers with molecular formula C4H10O and name them.

42. Write the crossed aldol condensation.

43. Identify A,B and C
$\overset{SoCl_2}\longrightarrow A \overset{NH_3}\longrightarrow B\overset{LiAH_4}\longrightarrow (C)$