Chemistry All India Set 3 2016-2017 Commerce (English Medium) Class 12 Question Paper Solution

Out of  which is an example of a benzylic halide?

What is the effect of adding a catalyst on Activation energy (E_a)

What is the effect of catalyst on: Gibbs energy (∆G)

Write the formula of the compound of iodine which is obtained when conc. HNO₃ oxidises I₂

What type of colloid is formed when a gas is dispersed in a liquid? Give an example

Write the IUPAC name of the following compound: 

Draw the structures of the following molecules: XeF₄

Draw the structures of the following: BrF₅

Write the name of the cell which is generally used in transistors. Write the reactions taking place at the anode and the cathode of this cell.

Arrange the following compounds in the increasing order of their acid strength:

p-cresol, p-nitrophenol, phenol

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

Write the structures of the products when Butan-2-ol reacts with CrO₃

Write the structures of the products when Butan-2-ol reacts with SOCl₂

Using IUPAC norms write the formulae for Potassium trioxalatoaluminate(III)

Using IUPAC norms write the formulae for Dichloridobis(ethane-1,2-diamine)cobalt(III)

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

What type of isomerism is shown by the complex [Co(NH₃)₅(SCN)]²⁺?

Why is [NiCl₄]²⁻ paramagnetic while [Ni(CN)⁴]²⁻ is diamagnetic? (Atomic number of Ni = 28)

Why are low spin tetrahedral complexes rarely observed?

Write one difference in Multimolecular colloid and Associated colloid

Write one difference in Coagulation and Peptization

Write one difference in Homogeneous catalysis and Heterogeneous catalysis

What are the dispersed phase and dispersion medium in milk?

Write one similarity between Physisorption and Chemisorption

Write the chemical method by which Fe(OH)₃ sol is prepared from FeCl₃.

The cell in which the following reaction occurs:

`2Fe^(3+) (aq) + 2I^(-) (aq) ---> 2Fe^(2+) (aq) + I_2 (s)` has `E_"cell"^@` = 0.236 V at  298 K. Calculate the standard Gibbs energy of the cell reaction. (Given : 1 F = 96,500 C mol⁻¹)

How many electrons flow through a metllic wire if a current of 0·5 A is passed for 2 hours? (Given : 1 F = 96,500 C mol⁻¹)

Based on the nature of intermolecular forces, classify the following solids:

Sodium sulphate, Hydrogen

What happens when CdCl₂ is doped with AgCl?

Give reasons:Ferrimagnetic substances show better magnetism than antiferromagnetic substances.

Explain the principle of the method of electrolytic refining of metals. Give one example.

Why does copper obtained in the extraction from copper pyrites have a blistered appearance?

What is the role of depressants in the froth floatation process?

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

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

Give reasons  Acetylation of aniline reduces its activation effect.

Give reasons for the following:

CH₃NH₂ is more basis than C₆H₅NH₂.

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

Give reasons for the following:

Red phosphorus is less reactive than white phosphorus.

Give reasons for the following:

Electron gain enthalpies of halogens are largely negative.

Give reasons for the following: N₂O₅ is more acidic than N₂O₃

Explain the following term with a suitable example:

Cationic detergents

What is meant by the term ‘broad spectrum antibiotics’? Explain.

Explain Tranquilizers

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

Teflon

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

Melamine – formaldehyde polymer

Write the name of monomers used for getting the following polymers : Neoprene

Following compounds are given to you :

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

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

2) Write the compound which is optically active.

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

A first order reaction takes 20 minutes for 25% decomposition. Calculate the time when 75% of the reaction will be completed.

(Given : log = 2 = 0·3010, log 3 = 0·4771, log 4 = 0·6021)

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, Ritu a class XII student decided to aware others about the adverse effects of these carcinogens in foods. She consultanted the school principal and requested him to instruct canteen contractor to stop selling sandwiches, pizza, burgers and other bakery products to the students. Principal took an immediate action and instructed the canteen contractor to replace the bakery products with some proteins and vitamins rich food like fruits, salads, sprouts etc. The decision was welcomed by the parents and students.

After reading the above passage, answer the following questions:

1) What are the values (at least two) displayed by Ritu?

2) Which polysaccharide component of carbohydrates is commonly present in bread?

3) Write the two types of secondary structure of proteins.

4) Give two examples of water soluble vitamins.

Write the product(s) in the following reactions:

Write the product(s) in the following reaction:

Write the product(s) in the following reactions: 

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

Butanal and Butan-2-one

Give simple chemical tests to distinguish between the following pairs of compounds:  Benzoic acid and Phenol

Write the equations involved in the following reactions:

Etard reaction

Write the reaction involved in the Stephen reduction

How will you convert the following in not more than two steps:

Benzoic acid to Benzaldehyde

How will you convert the following in not more than two steps:

Acetophenone to Benzoic acid

How will you convert the following in not more than two steps:

Ethanoic acid to 2-Hydroxyethanoic acid

Give reasons: Transition metals show variable oxidation states.

Account for the following: 

Zn, Cd and Hg are soft metals.

Account for the following:

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

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

Following are the transition metal ions of 3d series:

Ti⁴⁺, V²⁺, Mn³⁺, Cr³⁺

(Atomic numbers: Ti = 22, V = 23, Mn = 25, Cr = 24)

Answer the following:

1) Which ion is most stable in an aqueous solution and why?

2) Which ion is a strong oxidising agent and why?

3) Which ion is colourless and why?

Complete the following equations:

`2MnO_4^(-)+16H^++5S^(2-)rarr`

Complete the following equations:

 KMnO₄ 

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)

Define Molality.

Define the term Abnormal molar mass

30 g of urea (M = 60 g mol⁻¹) is dissolved in 846 g of water. Calculate the vapour pressure of water for this solution if vapour pressure of pure water at 298 K is 23·8 mm Hg.

Write two differences between an ideal solution and a non-ideal solution.