Class 12th Chemistry 2017 Set2 Outside Delhi Board Paper Solution

What is the effect of adding  a catalyst on :

(a) Activation Energy (E_a), and

(b) Gibbs Energy (ΔG) of a reaction ?

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

Write the IUPAC name of the following compound:

Write the formula of the compound of sulphur which is obtained when conc. HNO₃ Oxidises S₈.

Out of         , which is an example of vinylic halide.

Using IUPAC norms write the formulae for the following :

(a) Tris (ethane-1,2-diamine)chromium(III) chloride

(b) Potassium tetrahydroxozincate(II)

Draw the structure of the following:

(i) H₂S₂O₈

(ii) CIF₃

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

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 )

(a) Arrange the follwowing compounds in the increasing order of their strength:

               p-cresol,  p-nitrophenol,   phenol

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

                                          OR

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

(a) CrO₃

(b) SOCl₂

Write the principles of the following methods:

Vapour phase refining 

Write the role of dilute NaCN in the extraction of silver.

What is the role of collectors in the froth floatation process ? Give an example of a collector.

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

(a) The cell in which the following reactions occurs:

      Eo_cell   = 0.236 V at 298 K. Calculate the standard Gibbs energy of the cell reaction. (Given : 1F = 96,500 C mol-1)

(b) How many electrons flow through a metallic wire if a current of 0.5 A is passed for 2 hours ? (Given : 1F = 96,500 C mol-1)

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.

Give reasons for the following:

(a) Red phosphorus is less reactive than white phosphorus .

(b) Electron gain enthalpies of helogens are largely negative.

(c) N₂O₅ is more acidic than N₂O₃.

Define the following:

Anionic detergents

Define the following: 

Narrow spectrum antibiotics 

Define the following : 

Antacids

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

(a) Polyvinyl chloride (PVC)

(b) Melamine-formaldehyde polymer

(c) Buna-N

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.

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)

Write one difference in each of the following:

(a) Multimolecular colloid and Associated colloid

(b) Coagulation and Peptization

(c) Homogeneous catalysis and Heterogeneous catalysis

OR

(a) Write the dispersed phase and dispersion medium of milk.

(b) Write one similarity between Physisorption and chemisorption.

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

(a) What type of isomerism shown by the complex

    [Co(NH₃)₅ (SCN)]2+ ?

(b) Why is [NiCl₄]2-  paramegnatic while [Ni(CN)₄]2- is diamagnetic?

    (Atomic number of Ni = 28)

(c) Why are low spin tetrahedral complexes rarely observed?

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

Benzene, Silver

AgCl shows Frenkel defect while NaCl does not. Give reason.

What type of semiconductor is formed when Ge is doped with Al ?

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.

(a) 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 )

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 )

(b) Define the following terms:

    (i) Molality (m)

    (ii) Abnormal molar mass

OR

(a) 30g 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.

(b) Write two difference between ideal solution and non-ideal solutions.

(a) Write the product(s) in the following reactions

     (i) 

     (ii)          

    (iii)         

(b) Give simple chemical test to distinguish the following pairs of compound:

    (i) Butanal and Butan-2-one

    (ii) Benzoic acid and Phenol

                              OR

(a) Write the reactions involved in the following:

    (i) Etard reaction

    (ii) Stephon reduction

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

    (i) Benzoic acid to Benzaldehyde

Account for the following:

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 (+1.57V)  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 eqations:

1. 2MnO-₄   +   16H+  +   5S2-    → 

2. KMnO₄    →