Question Set B

cbse 12th Standard Chemistry Alcohols , Phenols and Ethers Model Questions Papers Study Material - QB365

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Questions:

Multiple Choice Question

20 x 1 = 20

A compond (X) with the molecular formula C₃H₈O can be oxidised to another compound (Y) whose molecular formula is C₃H₆O₂. The compound (X) may be

(a)

CH₃CH₂ - O - CH₃

(b)

(c)

CH₃ - CH₂ - CH₂ - OH

(d)

CH₃ - CH₂ - CHO

Dilution affects both conductivity as well as molar conductivity. Effect of dilution on both is as follows:

(a)

Both increase with dilution.

(b)

Both decreases with dilution

(c)

Conductivity increases whereas molar conductivity decreases on dilution.

(d)

Conductivity decreases whereas molar conductivity increases on dilution.

'X' is

(a)

(b)

(c)

(d)

The number of moles of KMnO₄ that will be needed to react with one mole of SO₃^2- in acidic solution.

(a)

(b)

3/5

(c)

4/5

(d)

2/5

When acidified K₂Cr₂O₇solution is added to Sn²⁺ salt then Sn²⁺changes to

(a)

(b)

Sn³⁺

(c)

Sn⁴⁺

(d)

Sn⁺

Consider the following statements in respect of lanthanides :
1. The basic strength of hydroxides of lanthanides increases from La (OH)₃ to Lu(OH)₃.
2. The lanthanide ions Lu³⁺,Yb²⁺ and Ce⁴⁺ are diamagnetic.
Which of the statement(s) given above is/ are correct ?

(a)

1 only

(b)

2 only

(c)

both 1 and 2

(d)

Neither 1 nor 2

The atomic number of cerium (Ce) is 58. The correct electronic configuration of Ce³⁺ ion is

(a)

\([Xe]{ 4f }^{ 1 }\)

(b)

\([Xe]{ 4f }^{ 1 }\)

(c)

\([Xe]{ 4f }^{ 13 }\)

(d)

\([Xe]{ 4d }^{ 1 }\)

In acidic medium, \({ MnO }_{ 4 }^{ 2- }\)

(a)

disproportionates to MnO₂ and \({ MnO }_{ 4 }^{ - }\)

(b)

is oxidized to \({ MnO }_{ 4 }^{ - }\)

(c)

is reduced to MnO₂

(d)

is reduced to Mn²⁺

Which of the following compounds will give a yellow precipitate with iodine and alkali?

(a)

Acetophenone

(b)

Methyl acetate

(c)

Acetamide

(d)

2-Hydroxypropane

10.

2-Methyl-2-propanol may be prepared by reacting methylmagnesium iodide with

(a)

propanone

(b)

ethyl ethanoate

(c)

ethanal

(d)

ethylene oxide

11.

Among the following sets of reactants which one produces anisole?

(a)

CH₃CHO; RMgX

(b)

C₆H₅OH; CH₃I

(c)

C₆H₅OH; neutral FeCl₃

(d)

C₆H₅CH₃; CH₃COCl; AlCl₃

12.

Products obtained when HI reacts with isopropyl methyl ether at 373 K are

(a)

isopropyl iodide and methyl alcihol

(b)

isopropyl alcohol and methyl iodide

(c)

isopropyl iodide and water

(d)

methyl iodide and water

13.

If the E⁰_cell for a given reaction has a negative value, then which of the following gives the correct relationships for the values of \({ \Delta G }^{ 0 }\) and K_eq ?

(a)

\({ \Delta G }^{ 0 }>0;{ K }_{ eq }<1\)

(b)

\({ \Delta G }^{ 0 }>0;{ K }_{ eq }>1\)

(c)

\({ \Delta G }^{ 0 }<0;{ K }_{ eq }>1\)

(d)

\({ \Delta G }^{ 0 }<0;{ K }_{ eq }<1\)

14.

The e.m.f. of the cell Zn | Zn²⁺ (0.01 M) || Fe²⁺ (0.001 M) | Fe at 298 K is 0.2905 volt. Then the value of equilibrium constant for the cell reaction is

(a)

\(\frac { 0.32 }{ { e }^{ 0.0295 } } \)

(b)

\(\frac { 0.32 }{ { 10 }^{ 0.0295 } } \)

(c)

\(\frac { 0.26 }{ { 10 }^{ 0.0295 } } \)

(d)

\(\frac { 0.32 }{ { 10 }^{ 0.0591 } } \)

15.

When measured against a standard calomel electrode, an electrode is found to have a standard reduction potential of 0.100 V. If standard reduction potential of calomel electrode is + 0.244 V and it acts as anode, the standard electrode potential of the same electrode against standard hydrogen electrode will be

(a)

- 0.144 V

(b)

+ 0.100 V

(c)

- 0.344 V

(d)

- 0.100 V

16.

Electrolysis of dilute aqueous NaCl solution was carried out by passing 10 milli ampere current. The time required to liberate 0.01 mol of H₂ gas at the cathode is (1 Faraday = 96500 C mol^-1)

(a)

9.65 x 10⁴ sec

(b)

19.3 x 10⁴ sec

(c)

28.95 x 10⁴ sec

(d)

38.6 x 10⁴ sec

17.

Which of the following is not a transition element ?

(a)

(b)

(c)

(d)

18.

What will happen during the electrolysis of aqueous solution of CuSO₄ by using platinum electrodes?

(a)

Copper will deposit at cathode

(b)

Copper will deposit at anode

(c)

Oxygen will be released at anode

(d)

Copper will dissolve at anode

19.

What will be the e.m.f of the given cell ? Pt | H₂ (P₁) | H⁺ (aq) | H₂ (P₂) | Pt

(a)

\(\frac { RT }{ F } In\frac { { P }_{ 1 } }{ { P }_{ 2 } } \)

(b)

\(\frac { RT }{ 2F } In\frac { { P }_{ 1 } }{ { P }_{ 2 } } \)

(c)

\(\frac { RT }{ F } In\frac { { P }_{ 2 } }{ { P }_{ 1} } \)

(d)

none of these

20.

A dilute aqueous solution of Na₂ SO₄ is electrolysed using platinum electrodes. The products at the anode and cathode are

(a)

O₂ , H₂

(b)

SO₂ , Na

(c)

O₂ , Na

(d)

S₂ O₈^2- , H₂

Assertion and reason

20 x 1 = 20

21.

Assertion: There is a continuous decrease in the size of lanthanoids.
Reason: Lanthanoids shows lanthanoid contraction.
Codes:
a) Both assertion and reason are true, and the reason is the correct explanation of the assertion.
b) Both assertion and reason are true but the reason is not the correct explanation of assertion.
c) Assertion is not true but the reason is true.
d) Both assertion and reason are false.

22.

Assertion: The addition of ammonium chloride to a solution containing ferric and magnesium ions is essential for selective precipitation of ferric hydroxide by aqueous ammonia.
Reason: The function of ammonium chloride is to suppress the Ionization of NH₄OH and thus check the precipitation of Mg(OH)₂.
Codes:
a) Both assertion and reason are true, and the reason is the correct explanation of the assertion.
b) Both assertion and reason are true but the reason is not the correct explanation of assertion.
c) Assertion is not true but the reason is true.
d) Both assertion and reason are false.

23.

Assertion : With HI at 373 K, ter-butyl methyl ether gives ter-butyl iodide and methanol.
Reason : The reaction occurs by SN² mechanism.
Codes:
(a) If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.
(b) If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
(c) If the Assertion is correct but Reason is incorrect.
(d) If both the Assertion and Reason are incorrect.

24.

Assertion : In Lucas test, 3º alcohols react immediately.
Reason : An equimolar mixture of anhyd. ZnCl₂ and conc. HCl is called Lucas reagent.
Codes:
(a) If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.
(b) If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
(c) If the Assertion is correct but Reason is incorrect.
(d) If both the Assertion and Reason are incorrect.

25.

Assertion: Zinc can be used while copper cannot be used in the recovery of Ag from the complex [Ag(CN)2 ] – .
Reason: Zinc is a powerful reducing agent than copper.
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) If assertion is true, but reason is false.
(d) If both assertion and reason are false

26.

Assertion (A) : Conductivity decreases with decrease in concentration of electrolyte.
Reason (R) : Number of ions per unit volume that carry the current in a solution decreases on dilution.
(a) Both (A) and (R) are correct and (R) is the correct explanation of (A).
(b) Both (A) and (R) are correct but (R) is not the correct explanation of (A).
(c) (A) is correct and (R) is incorrect.
(d) (A) is incorrect but (R) is correct.

27.

Assertion (A) C₂H₅OH is a weaker base than phenol but is a stronger nucleophile than phenol.
Reason (R) In phenol the lone pair of electrons or oxygen is withdrawn towards the ring due to resonance.
(a) Both (A) and (R) are correct, (R) is the correct explanation of (A).
(b) Both (A) and (R) are correct, (R) is not the correct explanation of (A).
(c) (A) is correct; (R) is incorrect.
(d) (A) is incorrect; (R) is correct.

28.

Assertion (A) : Copper is a non-transition element.
Reason (R) : Copper has completely filled d-otrbitals in its ground state.
(a) Both (A) and (R) are correct, (R) is the correct explanation of (A).
(b) Both (A) and (R) are correct, (R) is not the correct explanation of (A).
(c) (A) is correct; (R) is incorrect.
(d) (A) is incorrect; (R) is correct

29.

Assertion (A) p-methoxyphenol is a stronger acid than p-nitrophenol.
Reason (R) Methoxy group shows + I effect whereas nitro group shows -I effect.
(a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
(b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
(c) Assertion (A) is true, but Reason (R) is false.
(d) Asserton (A) is false, but Reason (R) is true.

30.

Assertion(A) Zr and HF are of almost similar atomic radii.
Reason (R) This is due to lanthanoid contraction.
(a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
(b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
(c) Assertion (A) is true, but Reason (R) is false.
(d) Asserton (A) is false, but Reason (R) is true.

31.

Assertion : Copper sulphate can be stored in zinc vessel.
Reason : Zinc is less reactive than copper.
Codes :
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
(c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.

32.

Assertion: E_Cellshould have a positive value for the cell to function.
Reason: E_cathode < E_anode
codes :
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
(c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.

33.

Assertion: Boiling points of alcohols are lower than hydrocarbons.
Reason: Among isomeric alcohols, boiling point decreases in the order: 1°> 2° > 3°.
Codes:
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
(c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.

34.

Assertion : If standard reduction potential for the reaction,
\(\mathrm{Ag}^{+}+e^{-} \rightarrow \mathrm{Ag}\) is 0.80 volt, then for the reaction
\(2 \mathrm{Ag}^{+}+2 e^{-} \rightarrow 2 \mathrm{Ag}\) it will be 1.60 volt.
Reason : If concentration of Ag⁺ ions is doubled, the standard electrode potential remains same .
Codes :
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
(c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.

35.

Assertion : If \(\lambda^{0}{ }_{\mathrm{Na}^{+}}\) and \(\lambda^{0}{ }_{\mathrm{Cl}^{-}}\) are molar limiting conductivities of the sodium and chloride ions respectively, then the limiting molar conductivity for sodium chloride is given by the equation, \(\Lambda_{\mathrm{NaCl}}^{\circ}=\lambda_{\mathrm{Na}^{+}}^{\circ}+\lambda_{\mathrm{Cl}^{-}}^{\circ}\)
Reason : This is according to Kohlrausch law of independent migration of ions.
Codes :
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
(c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.

36.

Assertion : Molar conductivity of a weak electrolyte at infinite dilution cannot be determined experimentally.
Reason : Kohlrausch law helps tofind the molar conductivity of a weak electrolyte at infinite dilution.
Codes :
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
(c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.

37.

Assertion: Zinc is used in the galvanisation of iron.
Reason: Its coating on iron articles increases their life by protecting them from rusting.
Codes:
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
(c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.

38.

In the following questions. an Assertion (A) is followed by a corresponding Reason (R) Use the following keys to choose the appropriate answer.
Assertion (A) Alcohols and phenols are soluble in water.
Reason (R) There occurs a dipole-dipole interaction of OH group of alcohol and phenol with water molecules which is responsible for their solubility in water.
Codes:
(a) Both (A) and (R) are correct, (R) is the correct explanation of (A).
(b) Both (A) and (R) are correct, (R) is not the correct explanation of (A).
(c) (A) is correct; (R) is incorrect.
(d) (A) is incorrect; (R) is correct.

39.

In the following questions an Assertion (A) is followed by a corresponding Reason (R) Use the following keys to choose the appropriate answer.
Assertion (A) La(OH)₂ is more basic than La(OH)₃.
Reason (R) The basic character of oxides and hydroxides decrease from La(OH)₂ to La(OH)₃.
Codes:
(a) Both (A) and (R) are correct, (R) is the correct explanation of (A).
(b) Both (A) and (R) are correct, (R) is not the correct explanation of (A).
(c) (A) is correct; (R) is incorrect.
(d) (A) is incorrect; (R) is correct.

40.

In the following questions.an Assertion (A) is followed by a corresponding Reason (R) Use the following keys to choose the appropriate answer.
Assertion (A) Conductivity always increases with decrease in concentration for strong and weak electrolytes.
Reason (R) Number of ions per unit volume decreases on dilution.
Codes:
(a) Both (A) and (R) are correct, (R) is the correct explanation of (A).
(b) Both (A) and (R) are correct, (R) is not the correct explanation of (A).
(c) (A) is correct; (R) is incorrect.
(d) (A) is incorrect; (R) is correct.

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Answers Key:

Multiple Choice Question

20 x 1 = 20

(d)
Conductivity decreases whereas molar conductivity increases on dilution.

(d)
2/5

(b)
2 only

(a)
\([Xe]{ 4f }^{ 1 }\)

(a)
disproportionates to MnO₂ and \({ MnO }_{ 4 }^{ - }\)

(d)
2-Hydroxypropane

10.

(a)
propanone

11.

(b)
C₆H₅OH; CH₃I

12.

(b)
isopropyl alcohol and methyl iodide

13.

(a)
\({ \Delta G }^{ 0 }>0;{ K }_{ eq }<1\)

14.

(b)
\(\frac { 0.32 }{ { 10 }^{ 0.0295 } } \)

15.

(b)
+ 0.100 V

16.

(b)
19.3 x 10⁴ sec

17.

(d)
Pb

18.

(a)
Copper will deposit at cathode

19.

(b)
\(\frac { RT }{ 2F } In\frac { { P }_{ 1 } }{ { P }_{ 2 } } \)

20.

(a)
O₂ , H₂

Assertion and reason

20 x 1 = 20

21.

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

22.

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

23.

24.

(b) If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.

25.

(a) If both assertion and reason are true and reason is the correct explanation of assertion.
Explanation:
Zinc is used in the recovery of Ag from the complex [Ag(CN)2]– whereas copper is not used because zinc is more powerful reducing agent than copper. Thus, both assertion and reason are true and reason is the correct explanation of assertion.

26.

(a) Both (A) and (R) are correct and (R) is the correct explanation of (A).

27.

(d) C₂H₅OH is a weaker acid than phenol as in phenol the lone pair of electrons on oxygen is withdrawn towards the ring due to resonance, leaving oxygen with a positive charge thus increasing acidity.

28.

(a) Both (A) and (R) are correct, (R) is the correct explanation of (A).

29.

(d) p-nitrophenol is more acidic than p-methoxyphenol. This is because the nitro group is an electron-withdrawing group, which stabilises the phenoxide ion formed when the phenol losses a proton, making it easier for the phenol to donate a proton and thus increasing its acidity.
Hence, Assertion (A) is false but Reason (R) is true.

30.

(a) Both (A) and (R) are true and (R) is the correct explanation of the (A).

31.

(d) Assertion is wrong statement but reason is correct statement.

32.

33.

(d): Alcohols undergo intermolecular H-bonding and hence, their boiling points are higher than those of hydrocarbons.
Among isomeric alcohols, boiling point decreases in the order: 1° > 2° > 3°.

34.

(d) : Standard reduction potential of an electrode has a fixed value

35.

(a) : According to Kohlrausch law, "limiting molar conductivity of an electrolyte can be represented as the sum of the individual contributions of the anion and cation of the electrolyte".

36.

(b) : In the plot of molar conductivity versus concentration, the extrapolation to zero concentration is not possible.

37.

(a): Zinc has no action of air or water on it and thus, its coating on iron articles increase their life by protecting them from rusting.

38.

(c) Solubility of alcohols and phenols in water is due to their ability to form hydrogen bonds with water molecules.
The solubility decreases with increase in size of the alkyl/aryl groups. Several lower molecular mass alcohols are miscible with water in all proportions. Hence, (A) is correct but (R) is incorrect.

39.

(b) La(OH)₃ is more basic than La(OH)₃. Due to lanthanoid contraction the size of lanthanoid ions decreases regularly with increase in atomic size. As a result of decrease in size their covalent character between lanthanoid ions and OH^- ions increase from La⁺³to Lu ⁺³. Therefore, the basic character of hydroxide decrease from La(OH)₃ to La(OH)₃, Thus, Both (A) and (R) are correct but (R) is not the correct explanation of (A).

40.

(d) Conductivity always decreases with decrease in concentration for weak and strong electrolytes. This is explained by the decrease in the number of ions per unit volume that carry current in solution on dilution. Thus, (A)is incorrect but (R)is correct.