Chemistry Outside Delhi Set 3 2022-2023 Science (English Medium) Class 12 Question Paper Solution

Auto-oxidation of chloroform in air and sunlight produces a poisonous gas known as ______.

Tear gas

Mustard gas

Phosgene gas

Chlorine gas

Phosphine 

Which among the following is an ambidentate ligand?

\[\begin{array}{cc}
\ce{COO-}\\
|\phantom{.....}\\
\ce{COO-}
\end{array}\]

\[\ce{NO^-_2}\]

\[\begin{array}{cc}
\ce{\overset{\bullet\bullet}{N}H3}
\end{array}\]

H₂O

Among the following, which has the highest value of pK_b?

The slope in the plot of `log  ["R"]_0/(["R"])` Vs. time for a first-order reaction is ______.

`(+"k")/2.303`

+k

`(-"k")/2.303`

−k

When D-glucose reacts with HI, it forms ______.

Gluconic acid

n-hexane

Saccharic acid

Iodohexane

Inversion of configuration occurs in ______.

S_N2 reaction

S_N1 reaction

Neither S_N2 nor S_N1 reaction

S_N1 as well as S_N2 reaction

Solubility of gas in liquid decreases with increase in ______.

Pressure

Temperature

Volume

Number of solute molecules

Which of the following relations is incorrect?

R = `1/"k"("l"/"a")`

G = `"k"("a"/"l")`

G = `"k"("l"/"a")`

∧_m = `"k"/"c"`

The reagent that can be used to distinguish acetophenone and benzophenone is ______.

2, 4-dinitrophenyl hydrazine

aqueous NaHSO₃

Fehling solution

I₂ and NaOH

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

HCHO

CH₃CHO

CH₃COCH₃

CH₃COC₂H₅

Which of the following compounds will undergo self-condensation in the presence of dilute NaOH solution?

C₆H₅CHO

CH₃CH₂CHO

(CH₃)₃C – CHO

H – CHO

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

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

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

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

`(+1)/2 ("d"["B"])/"dt"`

Which of the following transition metals shows +1 and +2 oxidation states?

Mn

Zn

Sc

Cu

The formula of the complex Iron (III) hexacyanidoferrate(II) is ______.

Fe₂ [Fe(CN)₆]₃

Fe₄ [Fe(CN)₆]₃

Fe [Fe(CN)₆]

Fe₃ [Fe(CN)₆]₂

Assertion (A): The enthalpy of mixing Δ_mix H is equal to zero for an ideal solution.

Reason (R): For an ideal solution the interaction between solute and solvent molecules is stronger than the interactions between solute-solute or solvent-solvent molecules.

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): Molar conductivity decreases with increase in concentration.

Reason (R): When concentration approaches zero, the molar conductivity is known as limiting molar conductivity.

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 show their highest oxidation state with oxygen.

Reason (R): The ability of oxygen to form multiple bonds to metals.

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: Chlorobenzene is resistant to nucleophilic substitution reaction at room temperature.

Reason (R): C–Cl bond gets weaker 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.

What are nucleic acids?

The two strands in DNA are not identical but are complementary. Explain.

Do the following conversions in not more than two steps:

CH₃COOH to CH₃COCH₃

Do the following conversions in not more than two steps:

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?

Write the equation involved in the following reaction:

Reimer-Tiemann reaction

Write the chemical equation involved in the following reactions:

Acetylation of salicylic add

Do the following conversions in not more than two steps:

\[\begin{array}{cc}
\ce{CH3CN to CH3 - C - CH3}\\
\phantom{...........}||\\
\phantom{...........}\ce{O}
\end{array}\]

Do the following conversions in not more than two steps:

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.