CHEMISTRY - XII
Volumetric Analysis
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Define the following terms i) Titration ii) Acidimetry
iii) Alkalimetry
iv) Indicators.
Give the formula for the following:
(a) Equivalent mass of an element
(b) Equivalent mass of an acid
(c) Equivalent mass of salt
(d) Equivalent mass of base
(e) Equivalent mass of oxidizing agent (f) Equivalent mass of radical
(g) Equivalent mass of reducing agent.
Define the following terms
a.
gram/liter
b. normality
c.
Decinormal solution
d. Molarity
e.
Molality
f. normality factor
What are the primary and secondary standard substance? What are the
requisites for a substance to become a primary standard solution
What is pH titration curve? Sketch pH curve for following with pH range
and suitable indicator.
(a) strong acid strong base
(b) strong acid weak base
(c) weak acid weak base
(d) weak acid strong base.
Strong acid and base: Strong acid and strong base
Weak acid and weak base Weak acid strong base
Define indicators? How is a suitable indicator selected for a particular
titration?
How much NaCl is produced when 100mL of N/10 HCl is mixed with
200mL of N/10 NaOH solution?
25.0 cc of an alkali solution is mixed with 8.0 cc of 0.75 N acid solution
and for complete neutralization. It further required 15.0 cc of .80 N acid
solution. Find the concentration of given alkali solution.
2.95 g of dibasic acid was dissolved in water and the solution was diluted
to 250 cc. 25 cc of the solution required 25 cc of N/5 Na2CO3 solution to
be neutralized. Calculate the equivalent weight and molecular weight of
acid.
Define the term basicity of acid, acidity of base, standard solution,
unknown solution, centinormal solution, molar solution and binormal
solution.
Define Lewis acid and Lewis base with and example of each. What are
Bronsted and Lowry acid and bases. What are the advantages and
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limitations of Bronsted and Lowry concept? Give conjugate acid and base
of ammonia.
What is a redox reaction? Why is it called so? Give an example of it.
State the relation between normality and molarity?
predict whether the aqueous solution of copper sulphate is acidic, basic or
neutral.
State Ostwald’s dilution law. what are its limitation?
Define pH of a solution and write the relation between pH and pOH.
Haloalkanes
Very short questions
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What are haloalkanes? How are they classified?
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Write the possible isomers of molecular formula C4H9Br and give their
IUPAC name.
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How do you prepare ethyl iodide from alcohol?
4.
Why is chloroform stored in a dark brown bottle?
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Why chloroform does not give white precipitate with aq. Silver nitrate?
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Why chlorobenzene does give orthao/ para product during electrophilic
substitution reaction?
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Define iodoform test.what type of molecule give positive iodoform test?
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Write three methods of preparation of chlorobenzene. How does it react
with i) methylchoride in the presence of dry ether ii) magnesium in THF.
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Account for the fact that C – X bond in halo benzene is stronger than that
of haloalkane. Nucleophilic substitution reaction in chlorobenzene is
difficult as compared to chloroethane. Why?
10. What happens when chlorobenzene is
i) heated with chloral in acidic medium.
11. Chlorobenzene undergoes electrophylic substitution in ortho and para
position.
12. Iodoethane when reacted with alcoholic silver cyanide gives compound A
which when treated with lithium aluminum hydride gives compound B.
Write the name and structure of compound A and B. Name the type of
reaction taking place in the making of A and B respectively.
13. Write down the structure of secondary haloalkane of molecular formulae
C3H7X . What happens when this compound is heated with sodium in dry
ether?
Short Questions
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How do you prepare chloroethane from ethane, ethanol and ethene
respectively? What happens when chlorethane is heated with i) sodium in
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the presence of ether ii) alc KOH
From ethane:
From ethanol:
From ethene:
Describe the lab preparation of chloroform from ethanol or acetone with
well labeled diagram.
What is Grighard reagent? How is it prepared? How does CH3CH2BrMg
reacts with
(i) H2O
(ii) H – CHO
(iii) CO2
What happens when,
(i) Chloroform is heated with silver power
(ii) Chloroform is heated with aniline in the presence of alc. NaOH
(iii) Chlorobenzene is treated with chloral.
(iv) Chloroform boiled with aq. KOH solution
(v) Ethyl iodide reacts with sodium ethoxide
Give one chemical reaction of following name reactions:
(a) Williamson's ether synthesis
(b) Sandmeyer's reaction
(c) Gattermann's reaction
(d) Wurtz-Fitting reaction
(e) Wurtz reaction
Conversion
(i) 1 - bromopropane to 2 - bromoproane
(ii) iodomethane to ethane
(iii) iodomethane to ethene
(iv) bromoethane to ethyene
Write short notes
(i) Markonikov's rule
(ii) Peroxide effect
Write uses of chloroform.
Chloroethane when heated with alcoholic potassium hydroxide produce
compound A. Compound A on treatment with ozone followed by
hydrolysis gives compound B. With clearly shown chemical reaction
identify compound A and B.
Aromatic Hydrocarbons (Benzene)
Very Short Questions
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Define aromatic hydrocarbons or arenes. With suitable example
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Write two general methods of preparation of benzene.
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Why is benzene called aromatic compound?
State Huckel's rule for aromaticity.
Define Friedel craft alkylation with example.
What happens when benzene is treated with
i)
chlorine in the presence of sunlight
ii) nitrating mixture at 60 degrees
iii) heated with acetic anhydride in the presence of anhydrous AlCl3
What happens when sodium benzoate is heated with soda lime?
Short Questions
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Write five characteristic features of aromatic compounds.
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How would you convert (a) acetylene to benzene (b) phenol to benzene
Aldehydes and Ketones
Short questions
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What are carbonyl compound? Give two examples with their IUPAC name
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Show your acquaintance with
i)
Aldol condensation reaction.
ii) Rosenmund’s reaction
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Why are aldehydes more reactive than ketones towards nuclephilic addition
reaction?
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Why the boiling point of aldehyde and ketones are lower than the
corresponding alcohols?
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Give one chemical test to distinguish methanal and ethanal. Give chemical
reaction too.
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What is urotropine. How is it obtained?
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Write the possible isomers of formula C4H8O and which isomer gives
iodoform test and why?
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What is perkin condensation and Cannizaro’s reaction? Give example of
each
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How would you prepare acetophenone and benzophenone.
10. What is Tollen’s reagent? What happens when ethanal is heated with
Tollen’s reagent?
11. Ethanal is reacted with methyl magnesium bromide to give product A ,
which is further hydrolyzed to give product B. What are A and B.
12. Give example of
(i) benzoin condensation reaction
(ii) Clemmensens reaction
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(iii) Carbonylation reaction
Ethanal reacts with hydrogen cyanide to form compound A, which when
hydrolyzed with acid gives compound B. What are compound A and B.
Ethanal reacts with iodine in presence of aqueous NaOH to give A, which
when heated with silver gives compound B. What are compound A and B?
What is Gattermann - Koch synthesis?
-CHO group is meta directing during electrophylic substitution reaction.
Explain.
Short Questions
1.
Write three general methods of preparation of aldehyde and ketones.
2.
What happens when
i)
Ethanal is heated with hydrazine in presence of glycerol.
ii) propanone is treated with sodium bisulphite in the presence of ethanol
iii) Ethanal is treated with 2,4 DNPH.
iv) propanone with phosphorous pentachloride
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What happens when
(a) Formaldehyde is warmed with Tollen's reagent?
(b) toluene is oxidized by CrO3, followed by hydrolysis
(c) benzyl chloride is heated with hydrogen in presence of palladium.
(d) Ethanal reacts with semicarbazide
(e) Benzaldehyde is warmed with conc. NaOH.
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Write the action of
(a) acetone with hydrazine
(b) propanone with 2, 4, - DNPH
(c) acetone is warmed with Iodine and aq. NaOH.
(d) ethanol with PCl5.
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What is a grignard reagent? how would you prepare primary, secondary
and tertiary alcohol using grignard reagent?
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(a) A carbonyl (X) gives addition product (Y) with methyl magnesium
bromide. The compound (Y) on hydrolysis gives iso-propyl alcohol.
Identify (X) and (Y).
(b) Convert acetaldehyde to acetone.
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An alcohol (A), reacts with thionyl chloride to produce (B), which on
dehydrohalogenation yielded a compound (C). The compound (C), on
ozonolysis gave the mixture of ethanal and methanal. If the alcohol, (A)
responses positive iodoform test. Identify A, B and C. How could you
convert the above compound, (B) into propanone?
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An organic compound A(C4H8O) forms phenyl hydrazone with phenyl
hydrazine and reduces Fehling's solution. It has negative iodiform test.
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Identify the organic compound A.
(a) A carbonyl (X) gives addition product (Y) with methyl magnesium
bromide. The compound (Y) on hydrolysis gives iso-propyl alcohol.
Identify (X) and (Y).
What happens when Benzaldehyde is treated with (a) aqueous NaOH (b)
LiAlH4 (c) alcoholic KCN (d) RMgBr (e) NH2NH2