12th Chemistry Paper Solutions Set 3 : CBSE All India Previous Year 2014

General Instructions:
(i) All questions are compulsory
(ii) Question numbers 1 to 8 are very short-answer questions and carry 1 mark each.
(iii) Question numbers 9 to 18 are short-answer questions and carry 2 marks each.
(iv) Question numbers 19 to 27 are also short-answer questions and carry 3 marks.
(v) Question numbers 28 to 30 are long-answer questions and carry 5 marks each.
(vi) Use Log Tables, if necessary. Use of calculators is not allowed.
Q1 :

What are the dispersed phase and dispersion medium in milk?


Answer :

In milk,
dispersion medium : Water
dispersed phase : Oil

Q2 :

Name the method used for refining of copper metal.


Answer :

Copper is refined by an electrolytic method. Pure copper is obtained at the cathode.

Q3 :

Why does NH3 act as a Lewis base?


Answer :

In an ammonia molecule, a lone pair of electrons is present over the nitrogen atom, which makes it a Lewis base.
 

Q4 :

The conversion of primary aromatic amines into diazonium salts is known as


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q5 :

Which of the following is a fibre?

Nylon, neoprene, PVC


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q6 :

Write the products of the hydrolysis of lactose.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q7 :

Identify the chiral molecule in the following pair:


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q8 :

Write the structure of 2-hydroxybenzoic acid.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q9 :

Complete the following equations:

(i) C + conc. H2SO4
(ii) XeF2 + H2O →


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q10 :

Draw the structures of the following:

(i) XeO3
(ii) H2SO4


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q11 :

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

(i) Teflon
(ii) Buna-N


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q12 :

An element with density 2.8 gcm−3 forms of f.c.c. unit cell with edge length 4 × 10−8 cm. Calculate the molar mass of the element.
(Given: NA = 6.022 Ã— 1023 mol​−1)


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q13 :

(a) Write the type of magnetism observed when the magnetic moments are aligned in parallel and anti-parallel directions in unequal numbers.

(b) Which stoichiometric defect decreases the density of the crystal?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q14 :

Define the following terms:

(i) Molar conductivity (â‹€m)
(ii) Secondary batteries


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q15 :

Write the mechanism of the following reaction:

CH3CH2OH -→HBrCH3CH2Br+H2O


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q16 :

For a chemical reaction R → P, the variation in the concentration R vs. time t plot is given as



(i) Predict the order of the reaction.
(ii) What is the slope of the curve?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q17 :

Write the principle behind the froth floatation process. What is the role of collectors in this process?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q18 :

Write the equations involved in the following reactions:

(i) Reimer–Tiemann reaction
(ii) Williamson synthesis


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q19 :

(i) Write the IUPAC name of the complex [Cr(NH3)4Cl2]CI.
(ii) What type of isomerism is exhibited by the complex [Co(en)3]3+?
     (en = ethane-1,2-diamine)
(iii) Why is [NiCl4]2- paramagnetic, but [Ni(CO)4] is diamagnetic?
      (At. nos. : Cr = 24, Co = 27, Ni = 28)


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q20 :

(a) Draw the structures of major monohalo products in each of the following reactions.

(i)
(ii)

(b) Which halogen compound in each of the following pairs will react faster in SN2 reaction?

(i) CH3Br or CH3I
(ii) (CH3)3C−Cl or CH3−Cl


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q21 :

Account for the following:
(i) Primary amines (R-NH2) have higher boiling point than tertiary amines (R3N).
(ii) Aniline does not undergo Friedel-Crafts reactions.
(iii) (CH3)2NH is more basic than (CH3)3N in an aqueous solution.


OR


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

(i) C6H5NO2 -→-------    Sn + HCl    A -→------273 KNaNO2 + HCl B 


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q22 :

On the occasion of the World Health Day, Dr Satpal organised a health camp for the poor farmers living in a nearby village. After check-up, he was shocked to see that most of the farmers suffered from cancer due to regular exposure to pesticides and many were diabetic. They distributed free medicines to them. Dr Satpal immediately reported the matter to the National Human Rights Commission (NHRC). On the suggestions of NHRC, the government decided to provide medical care, financial assistance, setting up of super speciality hospitals for treatment and prevention of the deadly disease in the affected villages all over India.
(i) Write the values shown by
(a) Dr Satpal
(b) NHRC
(ii) What type of analgesics are chiefly used for the relief of pain of terminal cancer?
(iii) Give an example of artificial sweetener that could have been recommended to diabetic patients.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q23 :

Define the following terms:

(i) Nucleotide
(ii) Anomers
(iii) Essential amino acids


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q24 :

(a) Calculate ∆rG° for the given reaction:
Mg (s) + Cu2+ (aq.) → Mg2+ (aq.) + Cu (s)
Given : E°cell = +2·71 V, 1 F = 96500 Cmol−1

(b) Name the type of cell which was used in Apollo space programme for providing electrical power.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q25 :

The following data were obtained during the first-order thermal decomposition of SO2Cl2 at a constant volume:
SO2Cl2 (g) → SO2 (g) + Cl2 (g)

Experiment Time/s−1 Total pressure/atm
1 0 0·4
2 100 0·7
Calculate the rate constant.
(Given: log 4 = 0·6021 and log 2 = 0·3010)


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q26 :

What are emulsions? What are their different types? Give one example of each type.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q27 :

Give reasons for the following:
(i) (CH3)3P = O exists but (CH3)3N = O does not.
(ii) Oxygen has less electron gain enthalpy with negative sign than sulphur.
(iii) H3PO2 is a stronger reducing agent than H3PO3.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q28 :

(a) Complete the following equations:
(i)  Cr2O72- + 2OH- â†’
(ii) MnO4- + 4H+ + 3e- â†’

(b) Account for the following:
(i) Zn is not considered as a transition element.
(ii) Transition metals form a large number of complexes.
(iii) The E° value for the Mn3+/Mn2+ couple is much more positive than that for Cr3+/Cr2+ couple.

 OR

(i) With reference to structural variability and chemical reactivity, write the differences between lanthanoids and actinoids.
(ii) Name a member of the lanthanoid series which is well known to exhibit +4 oxidation state.
(iii) Complete the following equation:
MnO


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q29 :

(a) Write the products formed when CH3CHO reacts with the following reagents:
     (i) HCN
     (ii) H2N−OH
     (iii) CH3CHO in the presence of dilute NaOH

(b) Give simple chemical tests to distinguish between the following pairs of compounds:
     (i) Benzoic acid and phenol
     (ii) Propanal and propanone


OR


(a) Account for the following:
     (i) CI−CH2COOH is a stronger acid than CH3COOH.
     (ii) Carboxylic acids do not give reactions of carbonyl group.

(b) Write the chemical equations to illustrate the following name reactions:
     (i) Rosenmund reduction
     (ii) Cannizzaro's reaction

(c) Out of CH3CH2−CO−CH2CH3 and CH3CH2CH2−CO−CH3, which gives iodoform test?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q30 :

(a) Define the following terms:
(i) Molarity
(ii) Molal elevation constant (Kb)

(b) A solution containing 15 g urea (molar mass = 60 gmol–1) per litre of solution in water has the same osmotic pressure (isotonic) as a solution of glucose (molar mass = 180 gmol–1) in water. Calculate the mass of glucose present in one litre of its solution.

OR

(a) What type of deviation is shown by a mixture of ethanol and acetone? Give reason.

(b) A solution of glucose (molar mass = 180 gmol–1) in water is labelled as 10% (by mass). What would be the molality and molarity of the solution?
(Density of solution = 1.2 gmL–1)


Answer :

Please Register/Login to get access to all solutions Facebook Login

12th Chemistry Paper Solutions Set 3 : CBSE Delhi Previous Year 2013 will be available online in PDF book soon. The solutions are absolutely Free. Soon you will be able to download the solutions.