12th Standard Chemistry English Medium Metallurgy Important Questions

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Questions:

Multiple Choice Question

59 x 1 = 59

The tertiary nitro compound is ___________

(a)

2-nitropropane

(b)

1-nitropropane

(c)

1-nitro-2, 2-dimethyl propane

(d)

2-nitro-2-methyl propane

The quality of a soap is described in term of _______

(a)

LDPE

(b)

HDPE

(c)

TFM (Total fatty matter)

(d)

LFM (Lowfatty matter)

The free radical polymerisation of the monomer 2 - chloro buta - l,3-diene gives _______________.

(a)

Buna N

(b)

Buna S

(c)

Neoprene

(d)

PHB

Electrolytic reduction of nitrobenzene in strongly acidic medium gives

(a)

aniline

(b)

p - aminophenol

(c)

m-nitroaniline

(d)

azoxybenzene

Disaccharides linked through the glycosidic carbon atoms of C₁ of glucose and C₂ of fructose are_______

(a)

non-reducing

(b)

reducing

(c)

both (a) and (b)

(d)

neither (a) nor (b)

Which is not a saturated fatty acid?

(a)

Palmitic acid

(b)

Stearic acid

(c)

Oleic acid

(d)

Glyceric acid

acid chloride + alcohol \(\longrightarrow\)?.

(a)

acids

(b)

amides

(c)

esters

(d)

amines

The metals near the bottom of the electro chemical series are ______.

(a)

strong reducing agents

(b)

strong oxidising agents

(c)

weak reducing agents

(d)

weak oxidising agents

The number of carbon atoms in a chain can be increased with _______ reaction.

(a)

Grignard

(b)

Cannizaro reaction

(c)

HVZ

(d)

Clemmensen

10.

What happens during the electrolysis of molten sodium chloride?

(a)

Cl₂ is released at the cathode

(b)

Liquid sodium is obtained at the anode

(c)

The emf of the overall reaction is -4.07 V

(d)

Cl₂ is released at the cathode and Liquid sodium is obtained at the anode

11.

Henderson equation for a weak acid and its salt is _______.

(a)

pH = pK_b+ log (Salt) / (Acid)

(b)

pH = pK_a + log (Salt) / (Acid)

(c)

pH = pK_a + log (Salt) / (Base)

(d)

pH = pK_a + log (Acid) / (Salt)

12.

The characteristic odour of lower phenol is _________.

(a)

carbolic acid

(b)

fruity

(c)

oil of bitter almond

(d)

rotten fish

13.

Which among the following has the highest pH?

(a)

1M NH₄ OH

(b)

1M HCI

(c)

1M NaOH

(d)

0.1 M NaOH

14.

Ethers in the presence of atmospheric oxygen oxidises to give hydroperoxides and dialkyl peroxides Such a spontaneous reaction by atmospheric oxygen is called ______.

(a)

auto oxidation

(b)

acylation

(c)

alkylation

(d)

dehydration

15.

An emulsion is a colloidal solution of _______.

(a)

two solids

(b)

two liquids

(c)

two gases

(d)

one solid and one liquid

16.

Which among the following does not affect adsorption?

(a)

surface area of the adsorbent

(b)

catalyst

(c)

temperature

(d)

pressure

17.

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

18.

Dettol is the mixture of _____________.

(a)

Chloroxylenol and bithionol

(b)

Chloroxylenol and \(\alpha\)-terpineol

(c)

phenol and iodine

(d)

terpineol and bithionol

19.

Which of the following amino acids are achiral?

(a)

Alanine

(b)

Leucine

(c)

Proline

(d)

Glycine

20.

Which of the following vitamins is water soluble?

(a)

Vitamin E

(b)

Vitamin K

(c)

Vitamin A

(d)

Vitamin B

21.

The order of basic strength for methyl substituted amines in aqueous solution is _________.

(a)

N(CH₃)₃> N(CH₃)₂H> N(CH₃)H₂> NH₃

(b)

N(CH₃)H₂>N(CH₃)₂H > N(CH₃)₃>NH₃

(c)

NH₃> N(CH₃)H₂> N(CH₃)₂ H>N(CH₃)₃

(d)

N(CH₃)₂H>N(CH₃)H₂> N(CH₃)₃> NH₃

22.

Which one of the following nitro compounds does not react with nitrous acid.

(a)

CH₃ -CH₂ -CH₂ -NO₂

(b)

(CH₃)₂ CH - CH₂NO₂

(c)

(CH₃)₃C NO₂

(d)

\({ CH }_{ 3 }-\underset { \overset { || }{ O } }{ C } -\underset { \overset { || }{ { CH }_{ 3 } } }{ CH } -{ NO }_{ 2 }\)

23.

An alkene “A” on reaction with O₃ and Zn - H₂O gives propanone and ethanol in equimolar ratio. Addition of HCl to alkene “A” gives “B” as the major product. The structure of product “B” is ______.

(a)

\(Cl-{ CH }_{ 2 }-CH_{ 2 }-\overset { \overset { CH_{ 3 } }{ | } }{ \underset { \underset { CH_{ 3 } }{ | } }{ CH } } \)

(b)

\({ H }_{ 3 }C-{ CH }_{ 2 }-\overset { \overset { CH_{ 2 }Cl }{ | } }{ CH } -{ CH }_{ 3 }\)

(c)

\(\\ { H }_{ 3 }C-{ CH }_{ 2 }-\overset { \overset { CH_{ 3 } }{ | } }{ \underset { \underset { CL{ } }{ | } }{ C } } -{ CH }_{ 3 }\)

(d)

\({ H }_{ 3 }C-{ CH }-\overset { \overset { CH_{ 3 } }{ | } }{ \underset { \underset { Cl }{ | } }{ C } } \)

24.

Phenyl methanal is reacted with concentrated NaOH to give two products X and Y. X reacts with metallic sodium to liberate hydrogen X and Y are ________.

(a)

sodium benzoate and phenol

(b)

Sodium benzoate and phenyl methanol

(c)

phenyl methanol and sodium benzoate

(d)

none of these

25.

One mole of an organic compound (A) with the formula C₃H₈O reacts completely with two moles of HI to form X and Y. When Y is boiled with aqueous alkali it forms Z. Z answers the iodoform test. The compound (A) is ______.

(a)

propan – 2-ol

(b)

propan -1-ol

(c)

ethoxy ethane

(d)

methoxy ehane

26.

Which of the following compound can be used as antifreeze in automobile rediators?

(a)

methanol

(b)

ethanol

(c)

Neopentyl alcohol

(d)

ethan -1, 2-diol

27.

Which one of the following is correctly matched?

(a)

Emulsion - Smoke

(b)

Gel - butter

(c)

foam - Mist

(d)

whipped cream - sol

28.

Which one of the following characteristics are associated with adsorption?

(a)

\(\Delta\)G and \(\Delta\)H are negative but \(\Delta\)S is positive

(b)

\(\Delta\)G and \(\Delta\)S are negative but \(\Delta\)H is positive

(c)

\(\Delta\)G is negative but \(\Delta\)H and \(\Delta\)S are positive

(d)

\(\Delta\)G, \(\Delta\)H and \(\Delta\)S all are negative.

29.

While charging lead storage battery _______.

(a)

PbSO₄ on cathode is reduced to Pb

(b)

PbSO₄ on anode is oxidised to PbO₂

(c)

PbSO₄ on anode is reduced to Pb

(d)

PbSO₄ on cathode is oxidised to Pb

30.

How many faradays of electricity are required for the following reaction to occur MnO₄^-→ Mn²⁺

(a)

(b)

(c)

(d)

31.

Dissociation constant of NH₄OH is 1.8 x 10^-5 the hydrolysis constant of NH₄Cl would be _______.

(a)

1.8 × 10^-19

(b)

5.55 × 10^-10

(c)

5.55 × 10^-5

(d)

1.80 × 10^-5

32.

What is the decreasing order of strength of bases
OH, NH₂^- H - C ≡ C and CH₃ - CH₂^-

(a)

OH^->NH₂^- >H-C≡C >CH₃^-CH₂^-

(b)

NH₂^->OH^->CH₃^-CH₂^- >H-C≡C

(c)

CH₃^-CH₂^->NH₂^->H-C≡C^->OH^-

(d)

OH^->H-C ≡ C^->CH₃^-CH₂^- >NH₂^-

33.

The half-life period of a first order reaction is 69.3 seconds. Its rate constant is ________.

(a)

10^-2 s^-1

(b)

10^-4 s^-1

(c)

10 s^-1

(d)

10² s^-1

34.

For a reaction: aA ⟶ bB, the rate of reaction is doubled when the concentration of A is increased by four times. The rate of reaction is equal to _____.

(a)

k[A]^a

(b)

\(k{ \left[ A \right] }^{ \frac { 1 }{ 2 } }\)

(c)

\(k{ \left[ A \right] }^{ \frac { 1 }{ a } }\)

(d)

K[A]

35.

The high reactivity of fluorine is due to________.

(a)

high ionisation energy

(b)

low bond dissociation energy

(c)

low electron affinity

(d)

high electro negativity

36.

Which reaction is not feasible.

(a)

\({ 2H }_{ 2 }O+{ 2F }_{ 2 }\longrightarrow 4HF+{ O }_{ 2 }\)

(b)

\(2 \mathrm{KBr}+\mathrm{I}_{2} \longrightarrow 2 \mathrm{KI}+\mathrm{Br}_{2}\)

(c)

\(2KBr+{ Cl }_{ 2 }\longrightarrow 2KCl+{ Br }_{ 2 }\)

(d)

\(2 \mathrm{KI}+\mathrm{Br}_{2} \longrightarrow 2 \mathrm{KBr}+\mathrm{I}_{2}\)

37.

ABAB type of packing is called _________.

(a)

hexagonal close packing

(b)

cubic close packing

(c)

tetragonal close packing

(d)

none of the above

38.

In a face centred cubic cell, an atom at the face contributes to the unit cell_______.

(a)

\(\frac{1}{4}\)Part

(b)

1Part

(c)

\(\frac{1}{2}\)Part

(d)

\(\frac{1}{8}\)Part

39.

Chemical formula of phosgene is_______.

(a)

COCl₂

(b)

CaOCl₂

(c)

CaCO₃

(d)

COCI

40.

Lewis acid character of boron trihalides is as a follows _______.

(a)

BF₃ > BCl₃ > BBr₃ > BI₃

(b)

BCI₃> BF₃ > BBr₃ > BI₃

(c)

BI₃ > BBr₃ > BCl₃ > BF₃

(d)

BI₃ > BF₃ > BCl₃ > BBr₃

41.

_________ is known as Bayer's reagent.

(a)

Hot dilute alkaline KMnO₄

(b)

Cold dilute alkaline KMnO₄

(c)

Hot Conc. acidic KMnO₄

(d)

Cold Conc. acidic KMnO₄

42.

Identify the paramagnetic species.

(a)

Cu⁺

(b)

Cr⁺

(c)

MnO₄

(d)

Zn²⁺

43.

Steel is an alloy of___________

(a)

iron and carbon

(b)

iron and calcium

(c)

copper and carbon

(d)

copper and iron

44.

Concentration of copper glance is done by________.

(a)

leaching

(b)

magnetic separation

(c)

froth flotation

(d)

hydraulic washing

45.

In an octahedral complex, the (n-1) d orbital are involved in hybridization. The complex is called ________ complex.

(a)

inner orbital

(b)

low spin

(c)

spin paired

(d)

all the above

46.

The hypothetical complex triamminediaqua chloridocobalt (III)chloride can be represented as _______.

(a)

[Co(NH₃)₃(H₂O)₂Cl]Cl₂

(b)

[Co(NH)₃(H₂O)Cl₃]

(c)

[Co(NH₂)₃(H₂O)₂Cl]

(d)

[Co(NH₃)₃(H₂O)₃]Cl₃

47.

In a reversible reaction, the enthalpy change and the activation energy in the forward direction are respectively −x kJ mol^-1 and y 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 10³J mol^-1

48.

For a reaction Rate = k[acetone]^3/2 then unit of rate constant and rate of reaction respectively is _______.

(a)

(mol L^-1 S^-1),(mol^1/2L^1/2S^-1)

(b)

(mol^-1/2L^1/2s^-1),(mol L^-1s^-1)

(c)

(mol^1/2L^1/2s^-1),(mol L^-1s^-1)

(d)

(mol L s^-1),(mol^1/2L^1/2s)

49.

The ionic radii of A⁺ and B⁻ are 0.98 x 10^-10 m and 1.81 x 10^-10m. the coordination number of each ion in AB is ________.

(a)

(b)

(c)

(d)

50.

In a solid atom M occupies ccp lattice and \(\left( \frac { 1 }{ 3 } \right) \) of tetrahedral voids are occupied by atom N. Find the formula of solid formed by M and N ________.

(a)

(b)

M₃N

(c)

MN₃

(d)

M₃N₂

51.

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

(a)

[Fe(CH₃-CH(NH₂)₂)₃](PO₄)₃

(b)

[Fe(H₂N-CH₂-CH₂-NH₂)₃](PO₄)

(c)

[Fe(H₂N-CH₂-CH₂-NH₂)₃](PO₄)₂

(d)

[Fe(H₂N-CH₂-CH₂-NH₂)₃]₃(PO₄)₂

52.

Which one of the following will give a pair of enantiomorphs?

(a)

[Cr(NH₃)₆][Co(CN)₆]

(b)

[Co(en)₂Cl₂]Cl

(c)

[Pt(NH₃)₄][PtCl₄]

(d)

[Co(NH₃)₄Cl₂]NO₂

53.

The catalytic behaviour of transition metals and their compounds is ascribed mainly due to _______.

(a)

their magnetic behaviour

(b)

their unfilled d orbitals

(c)

their ability to adopt variable oxidation states

(d)

their chemical reactivity

54.

Sc (Z = 21) is a transition element but Zinc (z = 30) is not because _______.

(a)

both Sc³⁺ and Zn²⁺ ions are colourless and form white compounds

(b)

In case of Sc, 3d orbital are partially filled but in Zn these are completely filled

(c)

last electron as assumed to be added to 4s level in case of zinc

(d)

both Sc and Zn do not exhibit variable oxidation states

55.

Which of the following is not sp² hybridised?

(a)

Graphite

(b)

graphene

(c)

Fullerene

(d)

dry ice

56.

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

(a)

Me₃SiCl

(b)

PhSiCl₃

(c)

MeSiCl₃

(d)

Me₂SiCl₂

57.

Which of the following is strongest acid among all?

(a)

(b)

(c)

HBr

(d)

HCl

58.

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.

59.

Which of the metal is extracted by Hall-Heroult process?

(a)

(b)

(c)

(d)

Assertion and reason

1 x 2 = 2

60.

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

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Answers Key:

Multiple Choice Question

59 x 1 = 59

(d)
2-nitro-2-methyl propane

(b)
p - aminophenol

(a)
non-reducing

(d)
Glyceric acid

(a)
strong reducing agents

(a)
Grignard

10.

11.

(b)
pH = pK_a + log (Salt) / (Acid)

12.

(a)
carbolic acid

13.

14.

(a)
auto oxidation

15.

(b)
two liquids

16.

(b)
catalyst

17.

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

18.

(b)
Chloroxylenol and \(\alpha\)-terpineol

19.

(d)
Glycine

20.

(d)
Vitamin B

21.

(d)
N(CH₃)₂H>N(CH₃)H₂> N(CH₃)₃> NH₃

22.

23.

24.

25.

26.

(d)
ethan -1, 2-diol

27.

(b)
Gel - butter

28.

Adsorption leads to decrease in randomnes (entropy).i.e, ΔS < 0 for the adsorption to occur, ΔG slhould be -ve. We know that ΔG = ΔH - TΔS if ΔS is -ve, TΔS is +ve.It means that ΔG will become negative only when ΔH is -ve and ΔH > TΔS.

29.

Charging anode:
PbSO_4(s) + 2e^- ➝ Pb_(s) + SO₄^2-_(aq)
Cathode:
PbSO_4(s) + 2H₂O_(I) ➝ PbO_2(s) + SO₄^2-_(aq) + 2e^-

30.

7MnO₄^- + 5e^- → Mn²⁺ + 4H₂O
5 moles of electrons i.e., 5F charge is required.

31.

\(K_h= { \frac { { K }_{ w } }{ K_b } } = \frac{1 \times 10^{-14}}{1.8 \times 10^{-5}}\)
= 0.55 x 10^-9 = 5.5 x 10^-10

32.

33.

(a)
10^-2 s^-1

34.

(b)
\(k{ \left[ A \right] }^{ \frac { 1 }{ 2 } }\)

35.

(b)
low bond dissociation energy

36.

(b)
\(2 \mathrm{KBr}+\mathrm{I}_{2} \longrightarrow 2 \mathrm{KI}+\mathrm{Br}_{2}\)

37.

(a)
hexagonal close packing

38.

39.

(a)
COCl₂

40.

41.

(b)
Cold dilute alkaline KMnO₄

42.

(b)
Cr⁺

43.

(a)
iron and carbon

44.

45.

(d)
all the above

46.

(a)
[Co(NH₃)₃(H₂O)₂Cl]Cl₂

47.

48.

Rate = k[A]ⁿ
Rate = \(\frac{-\mathrm{d}[\mathrm{A}]}{\mathrm{dt}}\)
unit of rate = \(\frac{mol L^{-1}}{s}\)=mol L^-1/s^-1
unit of rate constant
\(=\frac{ (mol{ L }^{ -1 }{ S }^{ -1 }) }{ ({ mol }{ L }^{ -1 })^n } \)
= mol^1-nL^n-1s^-1
in the case
rate = k [Acetone]^3/2
n = 3/2
= mol^1-(3/2)L^(3/2)-1s^-1
(mol^-(1/2)L^(1/2)s^-1).

49.

\(\left( \frac { r_{c^+} }{ r_{A^-} } \right) \) = \(\left( \frac { 0.98 \times 10^{-10 }}{ 1.81 \times 10^{-10} } \right) = 0.54\)
It is in the range of 0.414 to 0.732, hence the coordination number of each ion is 6.

50.

If the total number of M atoms is n, then the number of tetrahedral voids = 2n
Given that \(\left( \frac { 1 }{ 3 } \right) ^{rd}\) of tetrahedral voids are occupied.
i.,e \(\left( \frac { 1 }{ 3 } \right) \times 2n\) are occupied by N atoms
\(\therefore\)M : N = n : \(\left( \frac { 2 }{ 3 } \right) n\)
= 1 : \(\frac { 2 }{ 3 }\)
Hence M₃N₂ = 3 : 2