Chemistry Delhi Set 2 2013-2014 Commerce (English Medium) Class 12 Question Paper Solution

Give one example each of sol and gel.

Which reducing agent is employed to get copper from the leached low-grade copper ore?

Write the IUPAC name of the compound

Which of the following isomers is more volatile:

o-nitrophenol or p-nitrophenol?

Some liquids on mixing form 'azeotropes'. What are 'azeotropes'?

Arrange the following:

In increasing order of basic strength: C₆H₅NH₂, C₆H₅NHCH₃, C₆H₅CH₂NH₂.

Which component of starch is a branched polymer of α-glucose and insoluble in water?

Which of the following is a more stable complex and why ?

State Henry's Law. What is the effect of temperature on the solubility of a gas in a liquid?

Define the following terms:

Pseudo first-order reaction

Define the following terms:

Half-life period of reaction (t_1/2).

Write the principle behind the following methods of refining:

Hydraulic washing

Write the principle behind the following methods of refining:

Vapour-phase refining

Draw the structure of major monohalo product in each of the following reactions :

Draw the structure of major monohalo product in each of the following reactions :

Which alkyl halide from the following pair is chiral and undergoes faster S_N2 reaction?

Out of S_N1 and S_N2, which reaction occurs with

(a) Inversion of configuration
(b) Racemisation

Complete the following chemical equations :

Ca₃P₂ + H₂O →

Complete the following chemical equations :

Cu + H₂SO₄(conc.) →

Arrange the following in the order of the property indicated against each set :

HF, HCl, HBr, HI − increasing bond-dissociation enthalpy.

Arrange the following in the order of the property indicated against set :
H₂O, H₂S, H₂Se, H₂Te − increasing acidic character.

Write the IUPAC name of the complex [Cr(NH₃)₄Cl₂]⁺. What type of isomerism does it exhibit?

An element with density 11.2 g cm^–3 forms a f.c.c. lattice with edge length of 4 × 10^–8 cm.
Calculate the atomic mass of the element.
(Given : N_A = 6.022 × 10²³ mol^–1)

Examine the given defective crystal:

Answer the following questions :
(i) What type of stoichiometric defect is shown by the crystal?
(ii) How is the density of the crystal affected by this defect?
(iii) What type of ionic substances show such defect?

Calculate the mass of a compound (molar mass = 256 g mol⁻¹) to be dissolved in 75 g of benzene to lower its freezing point by 0.48 K (K_f = 5.12 K kg mol⁻¹).

Give the structures of A, B and C in the following reactions :

Give the structures of A, B and C in the following reactions :

How will you convert the following?

Nitrobenzene into aniline

How will you convert Ethanoic acid into methanamine

How will you convert the following?

Aniline into N−phenylethanamide

Write the mechanism of the following reaction :

Write the equation involved in the following reaction:

Reimer-Tiemann reaction

After the ban on plastic bags, students of a school decided to make people aware of the harmful effects of plastic bags on the environment and Yamuna River. To make the awareness more impactful, they organised a rally by partnering with other schools and distributed paper bags to vegetable vendors, shopkeepers and departmental stores. All the students pledged not to use polythene bags in the future to save the Yamuna River.

After reading the above passage, answer the following questions:
(i) What values are shown by the students?
(ii) What are bio-degradable polymers? Give one example.
(iii) Is polythene a condensation or an addition polymer?

Write the structures of the following molecules: XeOF₄

Draw the structures of the following molecules: BrF₃

Write the structural difference between white phosphorus and red phosphorus.

In reference to Freundlich adsorption isotherm, write the expression for adsorption of gases on solids in the form of an equation.

Write an important characteristic of lyophilic sols.

Based on the type of particles of dispersed phase, give one example each of associated colloid and multimolecular colloid.

Account for the following

Bi(V) is a stronger oxidizing agent than Sb(V).

Account for the following :

N − N single bond is weaker than P − P single bond.

Account for the following :

Noble gases have very low boiling points.

Name a sweetening agent used in the preparation of sweets for a diabetic patient.

What are antibiotics? Give ‘two’ examples

Give two examples of macromolecules that are chosen as drug targets

The following data were obtained during the first order thermal decomposition of SO₂Cl₂ at a constant volume :

SO₂Cl₂ (g) → SO₂ (g) + Cl₂ (g)

Calculate the rate constant.

(Given : log 4 = 0.6021, log 2 = 0.3010)

Deficiency of which vitamin causes night-blindness?

Give one example each for fibrous protein and globular protein.

Write the product formed on reaction of D-glucose with Br₂ water.

Write the products of the following reactions:

Write the products of the following reactions:

Write the products of the following reactions:

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

Benzaldehyde and Benzoic acid

Propanal and Propanone

Account for the following:

CH₃CHO is more reactive than CH₃COCH₃ towards reaction with HCN.

Account for the following:

Carboxylic acid is a stronger acid than phenol.

Write the chemical reaction involved in Wolff-Kishner reduction.

Write the chemical equations to illustrate the following name reactions:

Aldol condensation

Write the chemical equations to illustrate the following name reaction: 

Cannizzaro’s reaction

Define the following terms :

Limiting molar conductivity

Define the following term:

Fuel cell

Resistance of a conductivity cell filled with 0.1 mol L⁻¹ KCl solution is 100 Ω. If the resistance of the same cell when filled with 0.02 mol L⁻¹ KCl solution is 520 Ω, calculate the conductivity and molar conductivity of 0.02 mol L⁻¹KCl solution. The conductivity of 0.1 mol L⁻¹ KCl solution is 1.29 × 10⁻² Ω⁻¹ cm⁻¹.

State Faraday's first law of electrolysis.

How much charge in terms of Faraday is required for the reduction of 1 mol of Cu²⁺ to Cu?

Calculate emf of the following cell at 298 K:
Mg(s) | Mg²⁺(0.1 M) || Cu²⁺ (0.01) | Cu(s)
[Given E^o_cell = +2.71 V, 1 F = 96500 C mol^–1]

How do you prepare:

K₂MnO₄ from MnO₂?

How do you prepare:

Na₂Cr₂O₇ from Na₂CrO₄?

Account for the following:

Mn²⁺ is more stable than Fe²⁺ towards oxidation to +3 state.

Account for the following 

The enthalpy of atomisation is lowest for Zn in 3d series of the transition elements.

How do you prepare:

Actinoid elements show wide range of oxidation states.

Name the elements of 3d transition series that show maximum number of oxidation states. Why does this happen?

Which transition metal of 3d series has positive E° (M²⁺/M) value and why?

Out of Cr³⁺ and Mn³⁺, which is a stronger oxidising agent and why?

Name a member of the lanthanoid series that is well-known to exhibit +2 oxidation state.

Complete the following equation : MnO₄^- + 8H⁺ + 5e^- →