Class-XII
Chemistry
2nd Paper (Theorical)
Time: 3 hrs.
Full Marks-75
[N.B.
Figures on right side indicate full marks]
Section-A (Broad questions)
1. a) Describe
the condition for maximum production of ammonia from N2 and H2 by Habber process? 4
b) Conversion
of the following: 2 + 2=4 i)
Acetaldehyde from ethyne ii) 20 – hydroxy butanal from ethanal.
c) Explain
i) why does not nitrogen from NCl5 but phosphorous does from PCl5 2 + 2=4
ii) Alluminiam oxide is an amphoteric oxide
d) How will you test the presence of NO3-
in solution? 2
Or,
a) Describe the process of preparation of pure
ethanal in laboratory. 5
b) How carbonyl group converted into methylene
group? 2
c) The compounds of transition metals are
coloured Explain. 4
d) Write short note on 4
i)
Coupling reaction
ii) Canizzaro reaction
2. a) What is diazotization? Describe the
laboratory prepartion of benjene diazoniumchloride. 5
b) Write formula of the following 3
i)
Borax ii)
Chromite iii) Azurite
c) What is Schwettzer’s reagent? Write its
use 3
d) Write short notes on: 4
i) Optical isomerism ii) Stainless steel
Or,
a) Describe the laboratory preparation of
Aniline? 5
b) Complete the following reactions:
3
i) FeCl3
+ H2S ®
ii) SO2
(g) + NaOH (aq) ®
iii) NH3 (g) + Cl2 (g) ®
c) Write down the interconversion between
Ferrous salt and Ferric salt with equation.
3
d) Write down with reactions how the following
conversions can be made:
4
i) Ethanal from ethyne.
ii)
Phenol from benjene diazonium chloride.
3. a) Describe the reactions that occur when iron
is extracted from blaust furnace. 5
b) Write down the causes that the extraction of
Cu from copper pyrites is very difficult. 3
c) Write short notes on: 4
i)
Free radical ii) Disproportion
reaction
d) Arrange halogens hydracids according to their
strength and give logical supports. 3
Or,
a) Describe the principle of preparation of
sulphuric acid by contact process. 4
b) Write shorts notes on i) Carbonium ion ii) Hofmann degradation of amide 4
c) Complete the following reactions: 3
i) NH4NO3 ® ?
ii) NaCl +
MnCl2 + H2SO4 (conc) ® ?
iii) CH ºCH +
H2O ®
d) What is kelp? Describe the preparation of
iodine from kelp . 4
Section-B (Short answer questions)
4. a) Aniline is a weaker base than ammonia-Explain.
3
b) Describe SP2 hybridization with example 2
Or,
a) Explain why at normal temperature H2O
is a liquid but H2S is a gas . 3
b) Write down the formula:
2
i)
Vinyl Chloride ii) TSP
(2)
5. a) What is
acid rain ? Discuss its effects on Environment. 3
b) Explain:
Ethyne is acid in nature. 2
Or,
a) Write down the name in IUPAC system: 3
i) Br – CH = CH2 ii) 
iii) CH3–CH – CH–COOH
iii) CH3–CH – CH–COOH
║ │
│
O CH3 NH2
b) Write short notes on: Chiral carbon.
2
6. a) Diazoniam salt cannot be prepare from
primary aliphatic amine- Explain. 3
b) Write short notes on: Nessler’s reagent 2
Or,
a) Write down the interconversion between red
phosphorous and white phosphorous. 3
b) What are ligand and co-ordinating number? 2
7. a) Why nitrogen gas is use as a neutral medium? 3
b) Write short
notes on: Markovnikov’s rule. . 2
Or,
a) What is olium? . 2
b) Write down the name and formula of three
complexions 3
8. a) What is Tinture iodine?
3
b) What is racimic mixture? Give example of
racimic mixture and explain. 2
Or,
a) What is formalin? How it is prepared? 3
b) Write short notes on: Carbyl amine reaction.
2
9. a) Why the transitional elements shows variable
oxidation state? 3
b) What is enantiomer? Explain. 2
Or,
a) Explain that ethanal is more active than
propanone on necleophilic addition reaction? 3
b) Write short notes on: tautomerism 2
****
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