Chemistry Outside Delhi Set 1 2022-2023 Science (English Medium) Class 12 Question Paper Solution

The conversion of an alkyl halide into an alkene by alcoholic KOH is classified as ______.

a substitution reaction

an addition reaction

a dehydrohalogenation reaction

a dehydration reaction

The oxidation state of Fe in [Fe(CO)₅] is ______.

+2

0

+3

+5

Among the following, which is the strongest base?

The slope in the plot of ln[R] vs. time for a first order reaction is ______.

`(+k)/2.303`

– k

`(-k)/2.303`

+ k

An α-helix is a structural feature of ______.

Sucrose

Polypeptides

Nucleotides

Starch

Racemisation occurs in ______.

S_N1 reaction

S_N2 reaction

Neither S_N1 nor S_N2 reaction

S_N2 reaction as well as S_N1 reaction

Value of Henry's constant K_H ______.

increases with increase in temperature

decreases with increase in temperature

remains constant

first increases then decreases

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 reactions are feasible?

\[\ce{CH3CH2Br + Na^{+}O^{-}C(CH3)3 -> CH3CH2 - O - C(CH3)3}\]

\[\ce{(CH3)3 C - Cl + Na^{+}O^{-}CH2CH3 -> CH3CH2 - O - C(CH3)3}\]

Both \[\ce{CH3CH2Br + Na^{+}O^{-}C(CH3)3 -> CH3CH2 - O - C(CH3)3}\] and \[\ce{(CH3)3 C - Cl + Na^{+}O^{-}CH2CH3 -> CH3CH2 - O - C(CH3)3}\]

Neither \[\ce{CH3CH2Br + Na^{+}O^{-}C(CH3)3 -> CH3CH2 - O - C(CH3)3}\] nor \[\ce{(CH3)3 C - Cl + Na^{+}O^{-}CH2CH3 -> CH3CH2 - O - C(CH3)3}\]

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

HCHO

CH₃CHO

CH₃COCH₃

CH₃COC₂H₅

Which of the following does not give aldol condensation reaction?

CH₃ – CHO

CH₃COCH₃

For the reaction 3A `rightarrow` 2B, rate of reaction `+ (d[B])/(dt)` is equal to ______.

`(-3)/2 (d[A])/(dt)`

`(-2)/3 (d[A])/(dt)`

`(-1)/3 (d[A])/(dt)`

`+ (2d[A])/(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

The formula of the complex dichloridobis (ethane –1, 2-diamine) platinum(IV) nitrate is ______.

[Pt Cl₂(en)₂ (NO₃)₂]

[Pt Cl₂(en)₂] (NO₃)₂

[Pt Cl₂(en)₂ (NO₃)]NO₃

[Pt (en)₂ (NO₃)₂]Cl₂

Assertion (A) : Osmotic pressure is a colligative property.

Reason (R) : Osmotic pressure is proportional to the molality.

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) : 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.

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) : Nucleophilic substitution of iodoethane is easier than chloroethane.

Reason (R) : Bond enthalpy of C-I bond is less than that of C-Cl bond.

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?

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.