Chemistry Outside Delhi Set 2 2022-2023 Science (English Medium) Class 12 Question Paper Solution

Which of the following belongs to the class of vinyl halides?

CH₂ = CHCH₂CH₂Cl

\[\begin{array}{cc}
\ce{CH2 = C - CH3}\\
|\\
\phantom{.}\ce{Br}
\end{array}\]

CH₂ = CH – CH₂ – Br

CH ≡ C – Br

What is the secondary valency of cobalt in [Co(en₂)Cl₂]⁺?

6

4

2

8

When benzene diazonium chloride reacts with phenol, it forms a dye. This reaction is called ______.

Diazotisation reaction

Condensation reaction

Coupling reaction

Acetylation reaction

The slope in the plot of [R] Vs. time for a zero-order reaction is ______.

`(+"k")/2.303`

`(-"k")/2.303`

−k

+k

Proteins are polymers of ______.

Nucleic acids

Amino acids

Monosaccharides

Amines

Retention of configuration is observed in ______.

S_N1 reaction

S_N2 reaction

Neither S_N1 nor S_N2 reaction

S_N2 reaction as well as S_N1 reaction

An azeotropic mixture of two liquids will have a boiling point lower than either of the two liquids when it ______.

shows a negative deviation from Raoult's law

forms an ideal solution

shows a positive deviation from Raoult's law

is saturated

Which of the following solutions of KCl will have the highest value of molar conductivity?

0.01 M

1 M

0.5 M

0.1 M

Which of the following does not give Cannizzaro reaction?

(CH₃)₃C – CHO

(CH₃)₂ CH – CHO

HCHO

Which of the following is most reactive in nucleophilic addition reactions?

HCHO

CH₃CHO

CH₃COCH₃

CH₃COC₂H₅

Aldehydes and ketones react with hydroxylamine to form ______.

hydrazones

semicarbazones

cyanohydrins

oxime

For a reaction \[\ce{2A -> 3B}\], rate of reaction `-("d"["A"])/"dt"` is equal to ______.

`(+3)/2 ("d"["B"])/"dt"`

`(+2)/3 ("d"["B"])/"dt"`

`(+1)/3 ("d"["B"])/"dt"`

`+(2"d"["B"])/"dt"`

Which of the following characteristics of transition metals is associated with their catalytic activity?

Paramagnetic nature

Colour of hydrated ions

High enthalpy of atomisation

Variable oxidation states

Which one among the following metals of the 3d series has the lowest melting point?

Fe

Mn

Zn

Cu

Assertion (A): Elevation in boiling point is a colligative property.

Reason (R): The lowering of vapour pressure of solution causes elevation in boiling point.

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

Both (A) and (R) are true, but (R) is not the correct explanation of (A).

(A) is true, but (R) is false.

(A) is false, but (R) is true.

Assertion (A): Chlorobenzene is resistant to electrophilic substitution reaction.

Reason (R): C-Cl bond in chlorobenzene acquires partial double bond characters due to resonance.

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

Both (A) and (R) are true, but (R) is not the correct explanation of (A).

(A) is true, but (R) is false.

(A) is false, but (R) is true.

Assertion (A) : Copper is a non-transition element.

Reason (R) : Copper has completely filled d-orbitals in its ground state.

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

Both (A) and (R) are true, but (R) is not the correct explanation of (A).

(A) is true, but (R) is false.

(A) is false, but (R) is true.

Assertion (A): Transition metals have high enthalpy of atomisation.

Reason (R): Greater number of unpaired electrons in transition metals results in weak metallic bonding.

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

Both (A) and (R) are true, but (R) is not the correct explanation of (A).

(A) is true, but (R) is false.

(A) is false, but (R) is true.

The vapour pressure of pure liquid X and pure liquid Y at 25°C are 120 mm Hg and 160 mm Hg respectively. If equal moles of X and Y are mixed to form an ideal solution, calculate the vapour pressure of the solution.

Give reasons:

Mercury cell delivers a constant potential during its life time.

Give reasons:

In the experimental determination of electrolytic conductance, Direct Current (DC) is not used.

Define terms: Fuel cell

What advantage do the fuel cells have over primary and secondary batteries?

The conversion of molecules A to B follow second order kinetics. If concentration of A is increased to three times, how will it affect the rate of formation of B?

Explain pseudo-first-order reaction with an example.

Write the IUPAC name of the following:

[Co(NH₃)₅(ONO)]²⁺

Write the IUPAC name of the following:

K₂[NiCl₄]

What is a chelate complex? Give one example.

What are Heteroleptic complexes?

What is the difference between a nucleoside and nucleotide?

What products would be formed when a nucleotide from DNA containing thymine is hydrolysed?

Write the equation involved in the following reaction:

Kolbe’s reaction

Write the equations involved in the following reactions : Williamson synthesis

Write two differences between DNA and RNA.

Write the mechanism of the following reaction:

\[\ce{2CH3CH2OH ->[H^+][413 K] CH3-CH2-O-CH2-CH3 + H2O}\]

Why ortho-nitrophenol is steam volatile while para-nitrophenol is not?

What happens when Anisole is treated with CH₃Cl/anhydrous  AlCl₃?

What happens when Phenol is oxidised with Na₂Cr₂O₇/H⁺?

What happens when (CH₃)₃ C – OH is heated with Cu/573 K?

Write the chemical equation in support of your answer.

Which isomer of C₅H₁₀ gives a single monochloro compound C₅H₉Cl in bright sunlight?

Arrange the following compounds in increasing order of reactivity towards S_N2 reaction.

2-Bromopentane, 1-Bromopentane, 2-Bromo-2-methylbutane

p-Dichlorobenzene has higher m.p. and lower solubility than those of o- and m-isomers. Discuss.

Identify A and B in the following:

A first-order reaction is 50% complete in 30 minutes at 300 K and in 10 minutes at 320 K. Calculate activation energy (E_a) for the reaction. [R = 8.314 J K⁻¹ mol⁻¹]

[Given: log 2 = 0.3010, log 3 = 0.4771, log 4 = 0.6021]

When 19.5 g of F – CH₂ – COOH (Molar mass = 78 g mol⁻¹), is dissolved in 500 g of water, the depression in freezing point is observed to be 1°C. Calculate the degree of dissociation of F – CH₂ – COOH.

[Given: K_f for water = 1.86 K kg mol⁻¹]

Draw the geometrical isomers of [Co(en)₂Cl₂]²⁺. Which geometrical isomer of [Co(en)₂Cl₂]²⁺ is not optically active and why?

Write the hybridisation and magnetic behaviour of [CoF₆]³⁻.

[Given: Atomic number of Co = 27]

The following questions are case-based questions. Read the passage carefully and answer the questions that follow:

Answer the following:

(a) Write the name of the product when an aldehyde reacts with excess alcohol in the presence of dry HCl. (1)

(b) Why carboxylic acid is a stronger acid than phenol? (1)

(c) (i) Arrange the following compounds in increasing order of their reactivity towards CH₃MgBr: (1)

CH₃CHO, \[\begin{array}{cc}
\ce{(CH3)3C-C-CH3}\\
\phantom{....}||\\
\phantom{....}\ce{O}
\end{array}\],  \[\begin{array}{cc}
\ce{CH3-C-CH3}\\
||\\
\ce{O}
\end{array}\]

(ii) Write a chemical test to distinguish between propanal and propanone. (1)

OR

(c) Write the main product in the following: (2)

(i)
(ii)

The following questions are case-based questions. Read the passage carefully and answer the questions that follow:

Answer the following:

(a) The penta-acetate of glucose does not react with Hydroxylamine. What does it indicate? (1)

(b) Why cannot vitamin C be stored in our body? (1)

(c) Define the following as related to proteins: (2)

1. Peptide linkage
2. Denaturation

OR

(c) Define the following as related to carbohydrates: (2)

1. Anomers
2. Glycosidic linkage

Account for the following:

E° value for the Mn³⁺/Mn²⁺ couple is much more positive than that for Cr³⁺/Cr²⁺.

Account for the following:

Sc³⁺ is colourless whereas Ti³⁺ is coloured in an aqueous solution.

How do you prepare:

Actinoid elements show wide range of oxidation states.

Indicate the steps in the preparation of KMnO₄ from pyrolusite ore.

Account for the following:

Transition metals form alloys.

Account for the following:

Ce⁴⁺ is a strong oxidising agent.

Write one similarity and one difference between the chemistry of lanthanoid and actinoid elements.

Complete the following ionic equation:

\[\ce{Cr2O^{2-}7 + 2OH^- ->}\]

Account for the following:

Although the amino group is o, p-directing in aromatic electrophilic substitution reactions, aniline on nitration gives a substantial amount of m-nitroaniline.

Give reasons:

(CH₃)₂NH is more basic than (CH₃)₃N in an aqueous solution.

Give reasons for the following:

Ammonolysis of alkyl halides is not a good method to prepare pure primary amines.

Write the chemical equations involved in the following reactions:

Carbylamine reaction

Illustrate the following reaction giving suitable example in each case:Gabriel phthalimide synthesis

Write the structures of A, B and C in the following reaction:

Write the structures of A, B and C in the following reaction:

Give reasons for the following:

Aniline does not undergo Friedel- Crafts reaction.

Arrange the following in increasing order of their boiling point:

C₂H₅OH, C₂H₅NH₂, (C₂H₅)₃N

Conductivity of 2 × 10⁻³ M methanoic acid is 8 × 10⁻⁵ S cm⁻¹. Calculate its molar conductivity and degree of dissociation if `∧_"m"^0` for methanoic acid, is 404 S cm² mol⁻³.

Calculate the Δ_rG⁰ and log K_c, for the given reaction at 298 K:

\[\ce{Ni_{(s)} + 2Ag^+_{( aq)} <=> Ni^{2+}_{( aq)} + 2Ag_{(s)}}\]

Given: `"E"_("Ni"^(2+)//"Ni")^0` = −0.25 V, `"E"_("Ag"^+//"Ag")^0` = +0.80 V, 1F = 96500 C mol⁻¹.