DG KHAN BOARD 2017
PAPER CHEMISTRY PART-2
Time: 3:10 Hours
(Subjective Part)
Marks: 83
Section-I

2. Attempt any EIGHT short questions.

• Why is the ionic radius of a positive ion smaller than that of its neutral atom?
  
• Define hydration energy. Write an example.
  
• What is the action of heat on gypsum?
  
• Why is lime added to an acidic soil?
  
• Write four uses of borax?
  
• How-does aluminum react with concentrated Hydrochloric acid and concentrated sulphuric acid?
  
• Write two reactions for the preparation of the nitrogen oxide
  
• Write two dissimilarities between oxygen and sulphur.
  
• Define interstitial compounds. Write one example
  
• How are entrapped bubbles of eases removed during the preparation of steel?
  
• How are hydrocarbons produced by natural sources?
  
• What is the difference between chemical oxygen demand and Biochemical oxygen demand?

3. Attempt any EIGHT short questions.

• Why oxy acids of chlorine are stronger than oxy acids of Bromine?
  
• Describe - H - bonding in HF - molecule
  
• What are fossil fuels? How are they formed?
  
• Why compounds with (C = C) bond exhibit Geometric Isomerism?
  
• What is Raney Nickel. How is it produced?
  
• Write down structure (Formula) of (i) Vinyl chloride (ii) Vinyl Cyanide
  
• What objection were made on kekule formula of benzene?
  
• Write Mechanism for the reaction of Benzene with nitric Acid
  
• Justify that SN₁ — is uni — molecular SN₂ - is Bi - molecular
  
• Why Grignard’s reagent becomes so reactive?
  
• How Ethanol is denatured? Write name of two denaturating agents
  
• Write two reactions to confirm that compound is phenol

4. Attempt any SIX short questions.

• Give two chemical tests for the identification of aldehydes
  
• What is haloform reaction
  
• Write down structural formulas of the followings
  
  • Acetic anhydride
    
  • Valerie acid
    
• How amino acid is prepared by strecker method
  
• What is addition polymerization, give example
  
• What is saponification no.
  
• What is the difference between DNA and RNA
  
• Name two woody and two non woody raw materials used for the preparation of paper
  
• What are micronutrients?  

SECTION-II

Attempt any THREE questions.

5. (a) Why hydrogen can be placed above halogens? Justify
(b) Describe the two problems involved in the manufacture of caustic soda by Nelson cell and how i these problems were solved?

6. (a) Describe electrochemical theory to explain corrosion
(b) Write a note on water disinfection by chlorine

7. (a) Write a brief note on reforming of petroleum
(b) Explain mechanism of SN1 reactions with a suitable examples

8. (a) Bring about following conversions
(i) Methane to Ethane
(ii) Ethane to Methane
(b) Explain Cannizzaro’s Reaction with examples. Also give its mechanism

9. (a) Explain the structure of benzene according to atomic orbital treatment
(b) What is fermentation? How is ethyl alcohol obtained by fermentation of molasses and starch?