NDA CHEMISTRY PAST QUESTION ’13’

Check questions 1 – 20 here

 

 

21. The above equation represents the manufacture of
A. rubber
B. polyethene
C. polystyrene
D. butane

22. Dehydration of CH3 CH2CH2 CH2OH gives

A. CH2=CH-CH2CH3
B. CH2 CH=CH-CH3
C. CH=C-CH2-CH3
D. CH2C= CCH3

23. How many grammes of bromine will saturate 5.20g of but-l-ene-3-yne?

 

 

24. The best method to separate mixture of hexane (β  pt 41.9k) and heptanes
(β pt  371.6k) is ___.
A. simple distillation
B. fractional distillation
C. crystallization
D. chromatography

25. In a qualitative analysis, which of these elements: carbon, nitrogen, sulphur, chlorine and hydrogen are detected using silver nitrate?
A. carbon
B. sulphur
C. chlorine
D. nitrogen

26. Which of the following is NOT correct for sigma (σ) bond?
A. sigma bonds are stronger than Pi (ᴨ) bonds
B. They are formed by the side way overlap of atomic orbitals
C. They are formed by lateral overlap of atomic orbitals
D. They are responsible for the formation of single bonds

27. Which of the following organic compounds will dissolve readily in Benzene?
A. C7H16
B. C2H50H
C. CH3C – CH3
D. CH2H2 COOH

28. Geometrical isomers are:
A. isomers that are formed due to restricted rotation about double bond
B. isomers that are formed as a result of rotation about single bonds
C. isomers that are formed as a result of restricted rotation about triple bonds
D.  none of the above

29. The breakdown of large molecules in fuel oil into smaller ones needed in petrol is __.
A. cracking
B. catenation
C. combustion
D. catalytic desulphurization

30. C4H10 +13/2 012→ 4CO2 +5H20
The above equation is a ___.
A. cracking
B. combustion reaction of petrol
C. reduction reaction
D. carbonation

31. 2, 4 — dinitrophemy/hydrazine is a reagent used till testing the presence of ___.
A. Alcohols
B. carboxylic acids
C. Nitrites
D. carbonyl compounds

32. Kipp’s apparatus is used for the laboratory preparation of ___.
A. Sulphur
B. carbon dioxide
C. sulphur (iv) oxide
D. Nitrogen gas

33. Tollen reagent is used to differentiate between which pairs of organic compounds?
A. alcohols and ethers
B. amine and amide
C. aldehyde and ketones
D. carboxylic acid and esters

34. The solubility of solids increases with an increase in the temperature of solvent. Which of the following salts has its solubility unaffected with a rise in temperature?
A. KNO3
B. KI
C. KCI
D. NaCI

35. In the contact process for the manufacture of sulphuric acid, sulphur trioxide gas is not passed directly in water because
A. It is not so much soluble in water
B. It does not form sulphuric acid with water
C. Colloidal sulphur is deposited
D. A mist of fine chops of dilute sulphuric acid fill the pipes if direct
absorption in water is tried

36. Ammonia is used as a commercial refrigerant because:
A. It is a non-polar compound
B. The gas is very cheap
C. It is very soluble in water
d.     It is very easily liquefied and when allowed to evaporate, absorbs large quantities of heat producing low temperature

37.   9Fe2O3 +2NH3→ 6 Fe3O4  + N2  + 3H2O
According to the balanced equation above, when one mole of NH3 reacts completely. Which of the following is true?
A. I mole of N2, must be formed
B. 3 mole of Fe3O4 must be formed
C. 1 mole of water must be formed
D. 4 moles of Fe3O4 must react

38. What is the IUPAC name of the compound whose structure is shown below?

 

 

A. 1, 2 Methyl pentane
B. 2, 3 Dimethylpropane
C. 2, 2 Dimethylpropane
D. 1, 2 Dimethylpropane

39, The composition of gunpowder is
A. 50% HNO3 , 35% charcoal and 15% sulphur
B. 70% HNO3, 15% charcoal and 15% sulphur
C. 75% HNO3, 15% charcoal and 10% sulphur
D. 65% HNO3,25% charcoal and 10% sulphur

40. The correct arrangement of the petroleum fractions in order of increasing boiling points is
A. Petrol < kerosene < diesel oil
B. Petrol < diesel oil < kerosene
C. Kerosene < diesel oil < petrol
D. Diesel oil < kerosene < petrol

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