New ! Chemistry MCQ Practise Tests



Important 1 Mark Book Back Questions (New Syllabus) 2020

12th Standard

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Chemistry

Time : 00:30:00 Hrs
Total Marks : 36

    Part A

    36 x 1 = 36
  1. Which one of the following reaction represents calcinations?

    (a)

    \(2Zn+{ O }_{ 2 }\rightarrow 2ZnO\)

    (b)

    \(2ZnS+3O_{ 2 }\rightarrow 2ZnO+2SO_{ 2 }\)

    (c)

    \(MgCO_{ 3 }\rightarrow MgO+CO_{ 2 }\)

    (d)

    Both (a) and (c)

  2. Which one of the following is not feasible

    (a)

    Zn(s) + Cu2+(aq) \(\rightarrow\) Cu(s) + Zn2+(aq)

    (b)

    Cu(s)+ Zn2+(aq)\(\rightarrow\) Zn(s) + Cu2+(aq)

    (c)

    Cu(s) + 2Ag+(ag)\(\rightarrow\) 2Ag(s) + Cu2+(aq)

    (d)

    Fe(s) + Cu2+(aq) \(\rightarrow\) Cu(s)+ Fe2+(aq)

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

    (a)

    Aluminium

    (b)

    Calcium

    (c)

    Magnesium

    (d)

    Sodium

  4. The basic structural unit of silicates is _______.

    (a)

    \(\left( SiO_{ 3 } \right) ^{ 2- }\)

    (b)

    \(\left( SiO_{ 4 } \right) ^{ 2- }\)

    (c)

    \(\left( Sio \right) ^{ - }\)

    (d)

    \(\left( SiO_{ 4 } \right) ^{ 4- }\)

  5. Duralumin is an alloy of ______.

    (a)

    Cu, Mn

    (b)

    Cu, Al, Mg

    (c)

    Al, Mn

    (d)

    Al, Cu, Mn, Mg

  6. On hydrolysis, PCl3 gives________.

    (a)

    H3PO3

    (b)

    PH3

    (c)

    H3PO4

    (d)

    POCl3

  7. Assertion: Bond dissociation energy of fluorine is greater than chlorine gas
    Reason: Chlorine has more electronic repulsion than fluorine.
    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. Which of the following d block element has half filled penultimate d sub shell as well as half filled valence sub shell?

    (a)

    Cr

    (b)

    Pd

    (c)

    Pt

    (d)

    none of these

  9. Which of the following compounds is colourless?

    (a)

    Fe3+

    (b)

    Ti4+

    (c)

    Co2+

    (d)

    Ni2+

  10. MnO4- react with Br- in alkaline PH to give ________.

    (a)

    BrO3- MnO2

    (b)

    Br2, MnO42-

    (c)

    Br2, MnO2

    (d)

    BrO-, MnO42-

  11. 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.

  12. An excess of silver nitrate is added to 100ml of a 0.01M solution of Pentaaquachlorochromium (III)chloride. The number of moles of AgCl precipitated would be _______.

    (a)

    0.02

    (b)

    0.002

    (c)

    0.01

    (d)

    0.2

  13. Oxidation state of Iron and the charge on the ligand NO in [Fe(H2O)5NO]SO4 are_______.

    (a)

    +2 and 0 respectively

    (b)

    +3 and 0 respectively

    (c)

    +3 and -1 respectively

    (d)

    +1 and +1 respectively

  14. Which kind of isomerism is possible for a complex [Co(NH3)4Br2]CI?

    (a)

    geometrical and ionization

    (b)

    geometrical and optical

    (c)

    optical and ionization

    (d)

    geometrical only

  15. Solid CO2 is an example of ________.

    (a)

    Covalent solid

    (b)

    metallic solid

    (c)

    molecular solid

    (d)

    ionic solid

  16. The number of unit cells in 8 gm of an element X (atomic mass 40) which crystallizes in bcc pattern is (NA is the Avogadro number)________.

    (a)

    6.023 x 1023

    (b)

    6.023 x 1022

    (c)

    60.23 x 1023

    (d)

    \(\left( \frac { 6.023\times { 10 }^{ 23 } }{ 8\times 40 } \right) \)

  17. If ‘a’ is the length of the side of the cube, the distance between the body centered atom and one corner atom in the cube will be_________.

    (a)

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

    (b)

    \(\left( \cfrac { 4 }{ \sqrt { 3 } } \right) a\)

    (c)

    \(\left( \cfrac { \sqrt { 3 } }{ 4 } \right) a\)

    (d)

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

  18. For a first order reaction A ⟶ product with initial concentration x mol L-1, has a half life period of 2.5 hours. For the same reaction with initial concentration \(\left( \frac { x }{ 2 } \right) \) mol L-1 the half life is

    (a)

    (2.5 x 2) hours

    (b)

    \(\left( \frac { 2.5 }{ 2 } \right) \) hours

    (c)

    2.5 hours

    (d)

    Without knowing the rate constant, t1/2 cannot be determined from the given data

  19. 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.

  20. The solubility of BaSO4 in water is 2.42 × 10-3gL-1 at 298K. The value of its solubility product(Ksp) will be (Given molar mass of BaSO4 =233g mol-1)

    (a)

    1.08 × 10-14mol2L-2

    (b)

    1.08 × 10-12mol2L-2

    (c)

    1.08 × 10-10mol2L-2

    (d)

    1.08 × 10-8mol2L-2

  21. The button cell used is watches function as follows
    Zn (s) + Ag2O (s) + H2O (l) ⇌ 2Ag (s) + Zn2+ (aq) + 2OH-(aq) the half cell potentials are Ag2O (s) + H2O (l) + 2e- → 2Ag (s) + 2OH- (aq) E= 34V and Zn (s) → Zn2+ (aq) + 2e E0 = 0.76V . The cell potential will be_______.

    (a)

    0.84V

    (b)

    1.34V

    (c)

    1.10V

    (d)

    0.42V

  22. Conductivity of a saturated solution of a sparingly soluble salt AB (1:1 electrolyte) at 298K is 1.85 ×10−5 S m−1. Solubility product of the salt AB at 298K (Λom)AB = 14 ×10−3 S m2 mol−1.

    (a)

    5.7 x 10-12

    (b)

    1.32 x 10−12

    (c)

    7.5 x 10−12

    (d)

    1.74 x 10-12

  23. 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-.

  24. 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
  25. 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

  26. In the reaction Ethanol \(\overset { { PCl }_{ 5 } }{ \longrightarrow } X\overset { alc.KOH }{ \longrightarrow } Y\overset { { H }_{ 2 }{ SO }_{ 4 }/{ H }_{ 2 }O }{ \underset { 298k }{ \longrightarrow } } Z.\) The ‘Z’ is ______.

    (a)

    ethane

    (b)

    ethoxyethane

    (c)

    ethylbisulphite

    (d)

    ethanol

  27. Williamson synthesis of preparing dimethyl ether is a / an  ______.

    (a)

    SN1 reactions

    (b)

    SN2 reaction

    (c)

    electrophilic addition

    (d)

    electrophilic substitution

  28. 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)

  29. The reagent used to distinguish between acetaldehyde and benzaldehyde is _______.

    (a)

    Tollens reagent

    (b)

    Fehling’s solution

    (c)

    2,4 – dinitrophenyl hydrazine

    (d)

    semicarbazide

  30. In which of the following reactions new carbon – carbon bond is not formed?

    (a)

    Aldol condensation

    (b)

    Friedel craft reaction

    (c)

    Kolbe’s reaction

    (d)

    Wolf kishner reduction

  31. Aniline + benzoylchloride \(\overset { NaOH }{ \longrightarrow } \)C6H5 - NH - COC6 H5 this reaction is known as ______.

    (a)

    Friedel – crafts reaction

    (b)

    HVZ reaction

    (c)

    Schotten – Baumann reaction

    (d)

    none of these

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

    (a)

    carboxylic acid

    (b)

    aromatic acid

    (c)

    schiff ’s base

    (d)

    ketone

  33. Assertion: A solution of sucrose in water is dextrorotatory. But on hydrolysis in the presence of little hydrochloric acid, it becomes levorotatory.
    Reason: Sucrose hydrolysis gives unequal amounts of glucose and fructose. As a result of this change in sign of rotation is observed.
    Codes:
    a) If both accretion 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) If assertion is true but reason is false.
    d) if both assertion and reason are false.

    (a)

    If both accretion 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)

    If assertion is true but reason is false.

    (d)

    if both assertion and reason are false.

  34. 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

  35. Antiseptics and disinfectants either kill or prevent growth of microorganisms. Identify which of the following statement is not true.

    (a)

    dilute solutions of boric acid and hydrogen peroxide are strong antiseptics.

    (b)

    Disinfectants harm the living tissues

    (c)

    A 0.2% solution of phenol is an antiseptic while 1% solution acts as a disinfectant

    (d)

    Chlorine and iodine are used as strong disinfectants

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

    (a)

    antagonists

    (b)

    agonists

    (c)

    enzymes

    (d)

    molecular targets

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