#### 12th Standard English Medium Chemistry Reduced Syllabus One mark Important Questions with Answer key - 2021(Public Exam )

12th Standard

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Chemistry

Time : 01:00:00 Hrs
Total Marks : 50

Part A

50 x 1 = 50
1. Which one of the following reaction represents calcinations?

(a)

$2Zn+{ O }_{ 2 }\rightarrow 2ZnO$

(b)

$2ZnS+3O_{ 2 }\rightarrow 2ZnS+3O_{ 2 }\rightarrow 2ZnO_{ 2 }\rightarrow 2ZnO+2SO_{ 2 }$

(c)

$MgCO_{ 3 }\rightarrow MgO+CO_{ 2 }$

(d)

Both (a) and (c)

2. Which one of the following is not feasible

(a)

$Zn(s)+C{ u }^{ 2+ }\left( aq \right) \rightarrow Cu\left( s \right) +{ Zn }^{ 2+ }(aq)$

(b)

$Cu(s)+Z{ n }^{ 2+ }(aq)\longrightarrow Zn(s)+{ Cu }^{ 2+ }(aq)$

(c)

$Cu(s)+2Ag^{ + }(aq)\longrightarrow Ag(s)+{ Cu }^{ 2+ }(aq)$

(d)

$Fe(s)+{ Cu }^{ 2+ }(aq)\longrightarrow Cu(s)+{ Fe }^{ 2+ }(aq)$

3. Extraction of gold and silver involves leaching with cyanide ion. silver is later recovered by (NEET-2017)

(a)

Distillation

(b)

Zone refining

(c)

Displacement with zinc

(d)

liquation

4. Which of the following is not true with respect to Ellingham diagram?

(a)

Free energy changes follow a straight line. Deviation occurs when there is a phase change.

(b)

The graph for the formation of CO2 is a straight line almost parallel to free energy axis.

(c)

Negative slope of CO shows that it becomes more stable with increase in temperature

(d)

Positive slope of metal oxides shows that their stabilities decrease with increase in temperature

5. Which of the following metals has the largest abundance in the earth’s crust?

(a)

Aluminium

(b)

calcium

(c)

Magnesium

(d)

sodium

6. Which of these is not a monomer for a high molecular mass silicone polymer?

(a)

Me3SiCl

(b)

PhSiCl3

(c)

MeSiCl3

(d)

Me2SiCl2

7. 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

8. On hydrolysis, PCl3 gives

(a)

H3PO3

(b)

PH3

(c)

H3PO4

(d)

POCl3

9. Which one of the following compounds is not formed?

(a)

XeOF4

(b)

XeO3

(c)

XeF2

(d)

NeF2

10. Among the following the correct order of acidity is

(a)

HClO2 < HClO < HClO3 < HClO4

(b)

HClO4 < HClO2 < HClO < HClO3

(c)

HClO3 < HClO4 < HClO2 < HClO

(d)

HClO < HClO2 < HClO3 < HClO4

11. The magnetic moment of Mn2+ ion is

(a)

5.92BM

(b)

2.80BM

(c)

8.95BM

(d)

3.90BM

12. Permanganate ion changes to ________ in acidic medium

(a)

MnO42−

(b)

Mn2+

(c)

Mn3+

(d)

MnO2

13. The most common oxidation state of actinoids is

(a)

+2

(b)

+3

(c)

+4

(d)

+6

14. A magnetic moment of 1.73BM will be shown by one among the following (NEET)

(a)

TiCl4

(b)

[CoCl6]4-

(c)

[Cu(NH3)4]2+

(d)

[Ni(CN)4]2-

15. Formula of tris(ethane-1,2-diamine)iron(II)phosphate

(a)

[Fe(CH3-CH(NH2)2)3](PO4)3

(b)

[Fe(H2N-CH-CH2-NH2)3](PO4)

(c)

[Fe(H2N-CH2-CH2-NH2)3](PO4)2

(d)

[Fe(H2N-CH2-CH2-NH2-NH2)3]3(PO4)2

16. Solid CO2 is an example of

(a)

Covalent solid

(b)

metallic solid

(c)

molecular solid

(d)

ionic solid

17. The radius of an atom is 300pm, if it crystallizes in a face centered cubic lattice, the length oif the edge of the unit cell is

(a)

488.5pm

(b)

848.5pm

(c)

884.5pm

(d)

484.5pm

18. A zero order reaction X ⟶ XProduct, with an initial concentration 0.02M has a half life of 10 min. if one starts with concentration 0.04M, then the half life is

(a)

10 s

(b)

5 min

(c)

20 min

(d)

cannot be predicted using the given information

19. In a reversible reaction, the enthalpy change and the activation energy in the forward direction are respectively −x kJ mol-4 and kJ mol-1 Therefore , the energy of activation in the backward direction is

(a)

(y-x)kJ mol-1

(b)

(x+y)J mol-1

(c)

(x-y)KJ mol-1

(d)

(x+y) x 103Jmol-1

20. For the reaction ${ N }_{ 2 }{ O }_{ 5 }\left( g \right) \longrightarrow { 2NO }_{ 2 }\left( g \right) +\cfrac { 1 }{ 2 } { O }_{ 2 }\left( g \right)$ value of rate of disappearance of N2O5is given as 6.5 x 10-2 molL-1s-1 The rate of formation of NO2 and O2 is given respectively as

(a)

(3.25x10-2 mol L-1S-1) and (1.3 x10-2 mol L-1s-1

(b)

(1.3x10-2 mol L-1s-1) and (3.25 x10-2 mol L-1s-1)

(c)

(1.3x10-1 mol L-1s-1) and (3.25 x10-2 mol L-1s-1)

(d)

None of these

21. pH of a saturated solution of Ca(OH)2 is 9. The Solubility product ( Ksp) of Ca(OH)2

(a)

0.5 ×10-15

(b)

0.25 ×10-10

(c)

0.125 ×10-15

(d)

0.5 ×10-10

22. The dissociation constant of a weak acid is 1×10-3. In order to prepare a buffer solution with a pH = 4, the [Acid]/[Salt] ratio should be

(a)

4.3

(b)

3.4

(c)

10.1

(d)

1.10

23. The number of electrons delivered at the cathode during electrolysis by a current of 1A in 60 seconds is (charge of electron = 1.6 ×10−19C )

(a)

6.22 ×1023

(b)

6.022 ×1020

(c)

3.75 ×1020

(d)

7.48 ×1023

24. A gas X at 1 atm is bubble through a solution containing a mixture of 1MY- and 1MZ- at 25oC . If the reduction potential of Z>Y>X, then

(a)

Y will oxidize X and not Z

(b)

Y will oxidize Z and not X

(c)

Y will oxidize both X and Z

(d)

Y will reduce both X and Z

25. 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-.

26. Adsorption of a gas on solid metal surface is spontaneous and exothermic, then

(a)

ΔH increases

(b)

ΔS increases

(c)

ΔG increases

(d)

ΔS decreases

27. Which of the following compounds on reaction with methyl magnesium bromide will give tertiary alcohol.

(a)

benzaldehyde

(b)

propanoic acid

(c)

methyl propanoate

(d)

acetaldehyde

28. (CH3)3-C-CH(OH) CH3 $\overset { con{ H }_{ 2 }{ SO }_{ 4 } }{ \longrightarrow }$X (major product)

(a)

(CH3)3 CCH = CH2

(b)

(CH3)2C = C (CH3)2

(c)

CH2= C(CH3)CH2-CH2- CH3

(d)

CH2= C (CH3) - CH2- CH2- CH3

29. HO CH2 CH2 – OH on heating with periodic acid gives

(a)

methanoic acid

(b)

Glyoxal

(c)

methanol

(d)

CO2

30. Among the following ethers which one will produce methyl alcohol on treatment with hot HI?

(a)

(H3C)-3C-|-O-CH3

(b)

(CH3-)2-CH-CH2-O-CH3

(c)

CH3-(CH2)3-O-CH3

(d)

CH3-CH2-$\underset { \overset { | }{ { CH }_{ 3 } } }{ CH }$-O-CH3

31. Reaction of acetone with one of the following reagents involves nucleophilic addition followed by elimination of water. The reagent is

(a)

Grignard reagent

(b)

Sn / HCl

(c)

hydrazine in presence of slightly acidic solution

(d)

hydrocyanic acid

32. 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)

33. CH3Br $\overset { KCN }{ \longrightarrow } (A)\overset { { H }_{ 2 }{ O }^{ + } }{ \longrightarrow } (B)\overset { { PCl }_{ 5 } }{ \longrightarrow }$ (C) product (c) is

(a)

acetylchloride

(b)

chloro acetic acid

(c)

$\alpha$- chlorocyano ethanoic acid

(d)

none of these

34. Which one of the following reaction is an example of disproporationation reaction

(a)

Aldol condensation

(b)

cannizaro reaction

(c)

Benzoin condensation

(d)

none of these

35. Carboxylic acids have higher boiling points than aldehydes, ketones and even alcohols of comparable molecular mass. It is due to their

(a)

more extensive association of carboxylic acid via van der Waals force of attraction

(b)

formation of carboxylate ion

(c)

formation of intramolecular H-bonding

(d)

formation of intermolecular H – bonding

36. The method by which aniline cannot be prepared is

(a)

degradation of benzamide with Br2 / NaOH

(b)

potassium salt of phthalimide treated with chlorobenzene followed by hydrolysis with aqueous NaOH solution.

(c)

Hydrolysis of phenylcyanide with acidic solution

(d)

reduction of nitrobenzene by Sn / HCl

37. The product formed by the reaction an aldehyde with a primary amine

(a)

carboxylic acid

(b)

aromatic acid

(c)

schiff ’s base

(d)

ketone

38. When aniline reacts with acetic anhydride the product formed is

(a)

o – aminoacetophenone

(b)

m-aminoacetophenone

(c)

p – aminoacetophenone

(d)

acetanilide

39. Which of the following amines does not undergo acetylation?

(a)

t – butylamine

(b)

ethylamine

(c)

diethylamine

(d)

triethylamine

40. IUPAC name for the amine

(a)

3 – Bimethylamino – 3 – methyl pentane

(b)

3 (N,N – Triethyl) – 3- amino pentane

(c)

3 – N,N – trimethyl pentanamine

(d)

3– (N,N – Dimethyl amino) – 3- methyl pentane

41. Ammonium salt of benzoic acid is heated strongly with and the product so formed is reduced and then treated with NaNO2 / HCl at low temperature. The final compound formed is

(a)

Benzene diazonium chloride

(b)

Benzyl alcohol

(c)

Phenol

(d)

Nitrosobenzene

42. The central dogma of molecular genetics states that the genetic information flows from

(a)

Amino acids Protein DNA

(b)

DNA Carbohydrates Proteins

(c)

DNA RNA Proteins

(d)

DNA RNA Carbohydrates

43. The correct statement regarding RNA and DNA respectively is

(a)

the sugar component in RNA is an arabinos and the sugar component in DNA is ribose

(b)

the sugar component in RNA is 2’-deoxyribose and the sugar component in DNA is arabinose

(c)

the sugar component in RNA is an arabinose and the sugar component in DNA is 2’-deoxyribose

(d)

the sugar component in RNA is ribose and the sugar component in DNA is 2’-deoxyribose

44. The pyrimidine bases present in DNA are

(a)

(b)

Cytosine and Guanine

(c)

Cytosine and Thiamine

(d)

Cytosine and Uracil

45. Which of the following statement is correct?

(a)

Ovalbumin is a simple food reserve in egg-white

(b)

Blood proteins thrombin and fibrinogen are involved in blood clotting

(c)

Denaturation makes protein more active

(d)

Insulin maintains the sugar level of in the human body

46. $\alpha$-D (+) Glucose and β-D (+) glucose are

(a)

Epimers

(b)

Anomers

(c)

Enantiomers

(d)

Conformational isomers

47. Drugs that bind to the receptor site and inhibit its natural function are called

(a)

antagonists

(b)

agonists

(c)

enzymes

(d)

molecular targets

48. Natural rubber has _______.

(a)

alternate cis- and trans-configuration

(b)

random cis- and trans-configuration

(c)

all cis-configuration

(d)

all trans-configuration

49. An example of anti-fertility drug is ____________.

(a)

novestrol

(b)

seldane

(c)

salvarsan

(d)

Chloramphenicol

50. The polymer used in making blankets (artificial wool) is ________.

(a)

polystyrene

(b)

PAN

(c)

polyester

(d)

polythene