Chemistry- Sample Paper 1

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Subject: - Chemistry 1st Sample paper 201112 Time: - 3 hrs.

Standard: - 12th Max. Marks: - 70

General Instructions:

(i) All questions are compulsory.

(ii) Question number 1 to 8 are very short answer questions,carrying 1 mark each. Answer these in one word or aboutone sentence each.

(iii) Question number 9 to 18 are short-answer questions,carrying 2 marks each. Answer these in about 30 wordseach.

(iv) Question number 19 to 27 are also short answerquestions of 3 marks each. Answer these in about 40words each.

(v) Question number 28 to 30 are long answer questions5marks each. Answer in about 70 words each.

(vi) Use Log Table, if necessary. Use of calculators is not

permitted.

1. Sulphur octamerises into S8. What is the value of i for thisreaction.

2. In what way is a sol different from a gel?

3. State the role of silica in the metallurgy of copper.

4. What inspired N Bartlett for carrying out reaction

between Xe and PtF6?

5. Give the IUPAC name of the following compound:

6. Write the structural formula and IUPAC name of aspirin.

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7. Arrange the following in decreasing order of basic

strength in aqueous medium:

3352252252 )(,)(, NHandNHCNHHCNHHC

8. What is the difference between nylon-6 and nylon-6, 6?

9. Depict the galvanic cell in which the reaction

)(2)()(2)(22

sAgaqZnaqAgsZn ++++ takes place.

Further, show

a. Which of the electrodes is negatively charged?b. the carriers of the current in the cell.

c. Individual reaction at each electrode.

OR

Calculate the emf of the cell in which the following reaction

takes place:)(2)160.0()002.0(2)(

2sAgMNiMAgsNi ++

++

Given that VEcell

05.1=

10. Define the following:

a. Rate of reaction

b. Order of reaction.

11. Describe the role of the following:

a. NaCN in the extraction of silver.

b. Cryolite in the extraction of aluminium.

12. Complete the following chemical reactions / equations:

a. + .)(3 concHNOCu

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b. + 22)( ClOHCa

13. Write the balanced equations for the following:

a. +++

HFeMnO2

4

b. ++ + HIOCr 272

14. In the following pairs of halogen compounds which

compound undergoes SN2 reaction faster?

a. BrHCCHCHCBrCHHC ))((, 56356256

b.

15. Write the products of the following reactions:

a.

b.

OR

Give chemical test to distinguish between

compounds in the following pair of substances:

a. Pentan-2-ol and pentan-3-ol

b. Acetaldehyde and acetone

16. How are vitamins classified? Name the vitamin

responsible for coagulation of blood?

17. How do you explain the absence of aldehyde group in

pentaacetate fo glucose?

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b. There are two NH2 groups in semicarbazide.

However, only one is involved in the formation of

semicarbazone.

c. Carboxylic acids do not give properties of aldehydes

and ketones.

24. Giving a suitable example for each, explain the following:

a. Crystal field splitting

b. Linkage isomerism

c. Didentate ligand.

OR

Compare the following complexes with respect to

structural shapes of units, magnetic behaviour and hybrid

orbitals involved in units:

+ 3

64

3

63 ][,])([,])([ FeFCONiNHCo

25. Describe the following"

a. Disinfectants b. Anionic detergents

c. Analgesics

26. How would you account for the following:

a. Transition metals have high enthalpy of atomization.

b. Transition metals exhibit variable oxidation states.

c. Transition metals have a strong tendency to form

complexes?

27. Write short notes on the following:

a. Carbylamine reaction

b. Diazotisation

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c. Hoffmann's-bromamide reaction

28. a. Arrange the following compounds in increasing order

of their reactivity in nucleophilic addition reactions.

i. Ethanal, Propanal, Propanone, Butanone

ii. Benzaldehyde, p-Toluldehyde, p-

Nitrobenzaldehyde, Acetophenone.

b. An organic compound 69.77% carbon, 11.63%

hydrogen and rest oxygen. The molecular mass of the

compound is 86. It does not reduce Tollens' reagent

but forms an additional compound with sodium

hydrogen sulphite and gives a positive iodoform test.

On vigorous oxidation, it gives ethanoic acid and

propanoic acid. Write the possible structure of the

compound.

OR

a. Explain the mechanism of the following reactions:

i. Acid catalysed dehydration of an alcohol

forming an alkene.

ii. Acid catalysed hydration of an alkene

forming an alcohol.

b. How would you bring about the following

conversions:

i. Phenol to benzoquinone

ii. Benzoic acid to benzaldehyde

iii. Acetylene to acetaldehyde.

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29. a. Draw the structures of the following:

i. H2S2O8

ii. HClO4

b. Arrange the following in order of property indicatedfor each set:

i. F2, Cl2, Br2, I2 increasing bond dissociationenthalpy.

ii. HF, HCl, HBr, HI increasing acid strength.

iii. NH3, PH3, AsH3, SbH3, BiH3 increasing base

strength.

OR

a. Draw the structures of the following:

i. N2O4

ii. H4P2O7

b. Explain the following observations:

i. Why does PCl3 fume in moisture?

ii. Which form of sulphur shows paramagnetic

behaviour?

iii. Halogens have maximum negative electron gain

enthalpy in the respective periods of the periodic

table. Why?

30. Define the following:

a. Mole fraction

b. Azeotropic mixtures

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c. How many mL of a 0.1 M HCl are required to reactcompletely with 1 g mixture of Na2CO3 and NaHCO3containing equimolar amount of the two?

OR

a. What is meant by:

i. ebullisocopic constant

ii. van't Hoff factor

b. Determine the osmotic pressure of a solution

prepared by dissolving 25 mg of K2SO4 in 2 litre of

water at 25C, assuming that it is completely

dissociated.

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Chemistry- Sample Paper 1