Class 12th Chemistry 2017 Set1 Delhi Board Paper Solution

Write the formula of an oxo-anion of Manganese (Mn) in which it shows the oxidation state equal to its group member.

Write the IUPAC name of the following compound:

(CH₃CH₂)₂NCH₃

For a reaction R→ P, half life (t_1/2 ) is observed to be independent of the initial concentration of reactants. What is the order of reaction?

Write the structure of 1-Bromo-4-Chlorobut-2-ene

Write one similarity between Physisorption and Chemisorptions.

Complete the following reactions:

(i) NH₃ + 2Cl₂ (excess) 

(ii) X_eF₆ + 2H₂O 

                 OR

What happens when

(i) (NH₄)₂ Cr₂ O7 is heated?

(ii) H₃PO₃ is heated?

Write the equations?

Define the following terms:

(i) Colligative Properties

(ii) Molality (m)

Draw the structures of the following:

(i) H₂S₂O₇

(ii) X_eF₆

Calculate the degree of dissociation (α) acetic acid if its molar conductivity (Λ_m) is 39.05 S cm2/mol-1

Given λ0H+ = 349.6 S cm2mol-1      and    λ0(CH₃COO-) = 40.9 S cm2mol-1

Write the equations involved in the following reactions:

(i) Wolff-Kishner reduction

(ii) Etard reaction

A 10% solution (by mass) of sucrose in water has freezing point of 269.15 K. Calculate the freezing point of 10% glucose in water, if freezing point of pure water is 273.15 K.

Given : (Molar mass of sucrose = 342 g mol− 1 )

            (Molar mass of glucose = 180 g mol− 1 )

Calculate the mass of Ag deposited at cathode when a current of 2A was passed through a solution of AgNO₃ for 15 min.

(Given : Molar mass of Ag = 108 g mol−1 , 1F = 96500 C mol−1). 

Define fuel cell.

What type of isomerism is shown by the complex [Co(NH₃)₆] [Cr(CN)₆]

A solution of [Ni(H₂O)₆]2+ is green but a solution of [Ni(CN)₄]2- is colourless. Explain.

Write the IUPAC name of the following complex:

[Co(NH₃)₅ (CO₃)]Cl

Write one difference in each of the following:

1) lyophobic sols and lyophilic sol

2) Solution and Colloid

3) Homogeneous catalysis and Heterogeneous catalysis

Following data are obtained for the reaction:

N₂O₅ → 2NO₂ + 1/2 O₂

(a) Show that it follows first order reaction.

(b) Calculate the half-life.

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

The following compounds are given to you:

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

(a) Write the compound which is most reactive  towards S_N2 reaction.

(b) Write the compound which is optically active.

(c) Write the compound which is most reactive towards β-elimination reaction.

Write the principle of method used for the refining of germanium.

Out of PbS and PbCO₃ (ores of lead), which one is concentrated by froth floatation process preferably?

What is the significance of leaching in the extraction of aluminium?

Write structures of compounds A, B and C in each of the following reactions:

Do the following conversions in not more than two steps :

(a) Benzoic acid to benzaldehyde.

(b) Ethyl benzene to benzoic acid.

(c) Propanone to propene.

Write the structures of the monomers used for getting the following polymers:

(a) Dacron.

(b) Melamine-formaldehyde polymer.

(c) Buna-N.

Define the following:

Anionic detergents

Define the following: 

Antiseptic

Define the following: 

Broad spectrum antibiotics

Give reasons:

Thermal stability decreases from H₂O to H₂Te

Give reasons: 

Fluoride ion has higher hydration enthalpy than chloride ion. 

Give reasons: 

Nitrogen does not form pentahalide.

Give reasons:

Acetylation of aniline reduces its activation effect. 

Give reasons: 

CH₃ NH₂ is more basic than C₆H₅NH₂. 

Give reasons: 

Although - NH₂ is o/p directing group, yet aniline on nitration gives a significant amount of m-nitroaniline.

After watching a programme on TV about the presence of carcinogens (cancer causing agents) Potassium bromate and Potassium iodate in bread and other bakery products, Rupali a class XII student decided to make others aware about adverse affect of these carcinogens in foods. She consulted the school principal and requested him to instruct canteen contactor to stop selling sandwiches, pizzas, burgers and other bakery products to the students. The Principal took an immediate action and instructed to canteen contractor to replace the bakery products with some protein and vitamin rich food like fruit,salads,sprouts etc.The decision was welcomed by the parents and the students.

After reading the above passage, answer the following questions:

(a) What are the values (at least two) displayed by the Rupali?

(b) Which Polysaccharide component of carbohydrates is commonly present in bread?

(c) Write the two types of secondary structures of proteins.

(d) Give two examples of water solube vitamins.

Account for the following:

Transition metals form large number of complex compounds.

Account for the following:

The lowest oxide of transition metal is basic whereas the highest oxide is amphoteric or acidic.

Account for the following:

E° value for the Mn3 + / Mn2 + couple is highly positive (+1.57V)  as compare to Cr3 + / Cr2 + .

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

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

Out of Cu+ and Cu2+, which ion is unstable in aqueous solution and why?

Orange colour of Cr₂ O₇ 2 − ion changes to yellow when treated with an alkali. Why?

Chemistry of actinoids is complicated as compared to lanthanoids. Give two reasons

An element has atomic mass 93 g mol− 1 and density 11.5 gcm− 3 . If the edge length of its unit cell is 300 pm, identify the type of unit cell.

Write any two differences between amorphous solids and crystalline solids.

Calculate the number of unit cells in 8.1 g of aluminium if it crystallises in a f.c.c. structure. (Atomic mass of Al  =  27 g mol -1 )

Give reasons:

In stoichiometric defects, NaCl exhibits Schottky defect and not Frenkel defect.

Give reasons:

Silicon on doping with phosphorus forms n-type semiconductor.

Give reasons:

Ferrimagnetic substances show better magnetism than antiferromagnetic substances.

Write the products(s) in the following reactions: 

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

(i) Ethanol and phenol.

(ii) Propanol and 2-methylpropan-2-ol. 

Write the formula of reagents used in the following reactions:

(i) Bromination of phenol to 2, 4, 6-tribromophenol.

(ii) Hydroboration of propene and then oxidation to propanol.

Arrange the following compounds in the increasing order of the property indicated :

(i) p-nitrophenol, ethanol, phenol (acidic character).

(ii) Propanol, propane, propanal (boiling point).

Write the mechanism (using curved arrow notation) of the following reaction: