Friday, 22 May 2015

Chemistry for competitive exams – 07

01. Of the following chemicals which one is used in a refrigerator for cooling purposes?
(a)  radon   (b) Freon    (c) sodium   (d) fluorine
Ans. (b) Freon    

02. Proteins are assembled from this acid:
(a) Iodic acid (b) formic acid    (c) nitrous acid    (d) amino acid
Ans. (d) amino acid

03. Soda water contains :
(a) carbonic acid    (b) sulphuric acid    (c)carboxylic acid  (d) nitrous acid
Ans. (a) carbonic acid   

04. Which as is commonly used in balloons and airships:
(a) Hydrogen    (b) helium     (c) carbon dioxide  (d) Hydrogen sulphide
Ans. (b) helium  

05. Electric bulbs are filled with this gas
(a) oxygen  (b) carbon dioxide    (c) argon   (d) nitrogen
Ans. (c) argon

06. Which is the gas released by factors automobiles etc that is most harmful to life
(a) sulphur dioxide    (b)carbon dioxide    (c) nitrogen dioxide    (d) carbon monoxide
Ans. (c) nitrogen dioxide

07. A mixed of carbon monoxide and hydrogen it is a starting material for manufacturing a number of organic compounds is
(a) producer gas   (b) natural gas    (c) synthesis gas (d) water gas
(c) synthesis gas

08. An ionic bond can be formed between between two atoms when
(a) one of them has a low ionization energy and the other has a high electron affinity
(b)both the atoms have low values of ionization energy
(c) both the atoms have high values of ionization energy
(d) both the atoms have low values of electron affinity
Ans. (a) one of them has a low ionization energy and the other has a high electron affinity

09. Which of the following is required for the formation of an ionic bound
(a)  the total energy of the resulting molecule should be less than the total energy of the reactants
(b) an electron from the more electronegative element should be transferred to the less electronegative element
(c) the lattice energy of the resultant molecules should be as low as possible
(d) the ionic potentials of the reactants should be identical
Ans. (a) the total energy of the resulting molecule should be less than the total energy of the reactants

10. The cohesive energy of an ionic crystal is the energy
(a) liberated during the formation of the crystal from individual neutral atoms
(b) absorbed during the formation of the crystal from individual neutral atom    
(c) liberated during the formation of positive ions 
(d) absorved during the formation of negative ions 

Ans. (a) liberated during the formation of the crystal from individual neutral atoms

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