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Question Paper - Chemistry 2013 - 2014-CBSE 12th-Class 12 CBSE (Central Board of Secondary Education)

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SubjectChemistry
Year2013 - 2014 (March)

Alternate Sets

   
 Topics
 Marks
 Topics
 Marks

Marks: 70
Q: 1[1]

What is the effect of temperature on chemisorption ?

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Q: 2[1]

What is the role of zinc metal in the extraction of silver ?

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Q: 3[1]

What is the basicity of H3PO3 ?

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Q: 4[1]

Identify the chiral molecule in the following pair :

 

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Q: 5[1]

Which of the following is a natural polymer ?

Buna-S, Proteins, PVC

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Q: 6[1]

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

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Q: 7[1]

What are the products of hydrolysis of sucrose ?

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Q: 8[1]

Write the structure of p-methylbenzaldehyde.

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Q: 9[2]

An element with density 2.8 g cm–3 forms a f.c.c. unit cell with edge length 4 x 10–8 cm. Calculate the molar mass of the element.

(Given : NA = 6.022 x 1023 mol –1)

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Q: 10[2]
Q: 10.1[2]

What type of non-stoichiometric point defect is responsible for the pink colour of LiCl ?

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What type of stoichiometric defect is shown by NaCl ?

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Q: 10.2[2]

How will you distinguish between the following pairs of terms

Tetrahedral and octahedral voids

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How will you distinguish between the following pairs of terms :

Crystal lattice and unit cell

 

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Q: 11[2]

State Kohlrausch law of independent migration of ions. 

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Why does the conductivity of a solution decrease with dilution ?

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Q: 12[2]

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 ?

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Q: 13[2]

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

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Q: 14[2]

Complete the following equations :

P4 + H2O →

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Complete the following equations :

XeF4 + O2F2

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Q: 15[2]

Draw the structures of the following molecules:

XeF2

 

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Draw the structures of the following molecules:

BrF3

Write the structures of the following:

BrF3

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Q: 16[2]

Write the equations involved in the following reactions :

Reimer – Tiemann reaction

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Write the equations involved in the following reactions :

Williamson synthesis

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Q: 17[2]

Write the mechanism of the following reaction :

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Q: 18[2]

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

Bakelite

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

Neoprene

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Q: 19[3]

Calculate ΔrG° for the reaction

Mg (s) + Cu2+ (aq) → Mg2+ (aq) + Cu (s)

Given : E°cell = + 2.71 V, 1 F = 96500 C mol–1

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

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Q: 20[3]

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

SO2Cl2 (g) → SO2 (g) + Cl2 (g)

ExperimentTime/s–1Total pressure/atm
100.4
21000.7

Calculate the rate constant.

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

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Q: 21[3]

What are emulsions

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

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Q: 22[3]

Give reasons for the following :

(CH3)3 P = O exists but (CH3)3 N = O does not.

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Give reasons for the following :

Oxygen has less electron gain enthalpy with negative sign than sulphur.

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Give reasons for the following :

H3PO2 is a stronger reducing agent than H3PO3.

 

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Q: 23[3]

Write the IUPAC name of the complex [Cr(NH3)4 Cl2]Cl.

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What type of isomerism is exhibited by the complex [Co(en)3]3+?

(en = ethane-1,2-diamine)

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[NiCl4]2− is paramagnetic, while [Ni(CO)4] is diamagnetic, though both are tetrahedral. Why? (Atomic number of Ni = 28)

Why is [NiCl4]2– paramagnetic but [Ni(CO)4] is diamagnetic ? (At. nos. : Cr = 24, Co = 27, Ni = 28)

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Q: 24[3]

Draw the structures of major monohalo products in each of the following reactions :

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Draw the structures of major monohalo products in each of the following reactions :

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Which halogen compound in each of the following pairs will react faster in SN2 reaction

CH3Br or CH3I

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Which halogen compound in each of the following pairs will react faster in SN2 reaction

(CH3)3 C – Cl or CH3 – Cl

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Q: 25 | Attempt Any One[3]
Q: 25.1[3]

Give reasons for the following:

Primary amines have higher boiling point than tertiary amines.

Account for the following :

Primary amines (R-NH2) have higher boiling point than tertiary amines (R3N).

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Give reasons for the following:

Aniline does not undergo Friedal- Crafts reaction.

Account for the following :

Aniline does not undergo Friedel – Crafts reaction.

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Give reasons for the following:

(CH3)2NH is more basic than (CH3)3N in an aqueous solution.

Account for the following :

(CH3)2NH is more basic than (CH3)3N in an aqueous solution

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Q: 25.2[3]

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

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

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Q: 26[3]

Define the following terms as related to proteins :

Peptide linkage

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Define the following terms as related to proteins :

Primary structure

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Define the following terms as related to proteins:

Denaturation

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Q: 27[3]

On the occasion of World Health Day, Dr. Satpal organized 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 pains of terminal cancer ?

(iii) Give an example of artificial sweetener that could have been recommended to diabetic patients

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Q: 28 | Attempt Any One[5]
Q: 28.1[5]

Define the following terms :

Molarity

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Define the following terms :

Molal elevation constant (Kb)

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

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Q: 28.2[5]

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

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

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Q: 29[5]
Q: 29.1[5]

Complete the following equations

Cr2O72- + 2OH

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Complete the following equations

MnO4- + 4H+ + 3e- →

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Account for the following :

Zn is not considered as a transition element.

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How would you account for the following:

Transition metals form complex compounds.

Account for the following :

Transition metals form a large number of complexes.

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Account for the following :

The E° value for the Mn3+/Mn2+ couple is much more positive than that for Cr3+/Cr2+ couple.

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Q: 29.2[5]

With reference to structural variability and chemical reactivity, write the differences between lanthanoids and actinoids

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Name a member of the lanthanoid series which is well known to exhibit +4 oxidation state.

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Complete the following equation :

MnO4- + 8H+ + 5e- →

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Out of Mn3+ and Cr3+, which is more paramagnetic and why ?

(Atomic nos. : Mn = 25, Cr = 24)

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Q: 30 | Attempt Any One[5]
Q: 30.1[5]

Write the products formed when CH3CHO reacts with the following reagents :

HCN

 

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Write the products formed when CH3CHO reacts with the following reagents

H2N – OH

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Write the products formed when CH3CHO reacts with the following reagents

CH3CHO in the presence of dilute NaOH

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

 Benzoic acid and Phenol

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

Propanal and Propanone

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Q: 30.2[5]

Account for the following :

Cl – CH2COOH is a stronger acid than CH3COOH.

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Why carboxylic acid does not give reactions of carbonyl group?

Account for the following :

Carboxylic acids do not give reactions of carbonyl group.

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Write the chemical equations to illustrate the following name reactions :

Rosenmund reduction

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Write the chemical equations to illustrate the following name reactions :

Cannizzaro’s reaction

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Out of CH3CH2 – CO – CH2 – CH3 and CH3CH2 – CH2 – CO – CH3, which gives iodoform test?

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