Chemistry Term 2 - Outside Delhi Set 3 2021-2022 Science (English Medium) Class 12 Question Paper Solution

An organic compound (A) with molecular formula C₃H₇NO on heating with Br₂ and KOH forms a compound (B). Compound (B) on heating with CHCl₃ and alcoholic KOH produces a foul-smelling compound (C) and on reacting with C₆H₅SO₂Cl forms a compound (D) which is soluble in alkali. Write the structure of (A), (B), (C) and (D).

Write the product formed when benzaldehyde reacts with the following reagent:

CH₃CHO in the presence of dilute NaOH.

Write the product formed when benzaldehyde reacts with the following reagent:

H₂N–OH in the presence of a weak acid.

Write the product formed when benzaldehyde reacts with the following reagent:

Tollen’s reagent

The conductivity of 0.001M acetic acid is 7.8 × 10⁻⁵ S cm⁻¹. Calculate its degree of dissociation if `∧_m^0` for acetic acid is 390 S cm² mol⁻¹.

Transition metals show high melting points why?

Give reasons for the following:

The transition metals generally form coloured compounds.

Why E⁰ value for Mn³⁺/Mn²⁺ couple is highly positive?

Which acid of the following pair would you expect to be stronger?

F−CH₂−COOH or CH₃−COOH

Arrange the following compounds in increasing order of their boiling points:

CH₃CH₂OH, CH₃−CHO, CH₃−COOH

Give a simple chemical test to distinguish between the following pair of compounds:

Benzaldehyde and Acetophenone

Which will undergo faster nucleophilic addition reaction?

Acetaldehyde or Propanone

What is the composition of Fehling's reagent?

Draw the structure of the semicarbazone of ethanal.

Give reasons for the following:

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

Aniline does not give Friedel-Crafts reaction. Give a reason.

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.

What happens when propanone is treated with CH₃MgBr and then hydrolysed?

What happens when ethanal is treated with excess ethanol and acid?

What happens when methanal undergoes cannizzaro reaction?

Write the main product in the following reaction:

\[\ce{2CH3COCl + (CH3)2Cd ->}\]

Write the main product in the following reaction:

\[\ce{CH3CH2CHO ->[Zn(Hg)/Conc. HCl]}\]

Write the main product in the following reaction:

Differentiate between the following:

Adsorption and Absorption

Differentiate between the following:

Lyophobic Sol and Lyophilic Sol

Differentiate between the following:

Multimolecular Colloid and Macromolecular colloid

Define the following term:

Zeta potential

Define coagulation.

Why a negatively charged sol is obtained when AgNO₃ solution is added to KI solution?

Define transition metals.

Why Zn, Cd and Hg are not called transition metals?

How is the variability in oxidation states of transition metals different from that of p-block elements?

Using valence bond theory, predict the hybridization and magnetic character of the complex:

[Ni(CO)₄] (Atomic number: Ni = 28)

Write IUPAC name of [Pt(NH₃)₂Cl(NO₂)].

Why [Co(en)₃]³⁺ is a more stable complex than [Co(NH₃)₆]³⁺?

Calculate Δ_rG⁰ and log K_c for the following cell:

\[\ce{Ni(s) + 2Ag^+(aq) -> Ni^{2+}(aq) + 2Ag(s)}\]

Given that \[\ce{E^0_{cell}}\] = 1.05 V, 1F = 96,500 C mol^–1.

Calculate the e.m.f. of the following cell at 298 K:

Fe(s) | Fe²⁺ (0.001 M) | | H⁺ (0.01 M) | H₂(g) (1 bar) | Pt(s)

Given that \[\ce{E^0_{cell}}\] = 0.44 V

[log 2 = 0.3010, log 3 = 0.4771, log 10 = 1]

Read the following passage and answer the questions that follow:

1. What is the effect of temperature on the rate constant of a reason?    [1]
2. For a reaction \[\ce{A + B → Product}\], the rate law is given by, Rate = k[A]² [B]^1/2. What is the order of the reaction?    [1]
3. How order and molecularity are different for complex reactions?    [1]
4. A first-order reaction has a rate constant 2 × 10^–3 s^–1. How long will 6 g of this reactant take to reduce to 2 g?    [2]
   OR
   The half-life for radioactive decay of ¹⁴C is 6930 years. An archaeological artifact containing wood had only 75% of the ¹⁴C found in a living tree. Find the age of the sample.
   [log 4 = 0.6021, log 3 = 0.4771, log 2 = 0.3010, log 10 = 1]    [2]