Surface Chemistry Quiz-16

Surface Chemistry Quiz-16

Dear Readers,

The one subject in NEET which is candidates who can easily attain good marks is Chemistry. That's the reason, often, one doesn’t pay notice and choose to compromise it. But if one wants to rank above others, the tip is to be thorough with NEET chemistry concepts. The understanding of reactions and definite basic understanding is what requires major attention in Chemistry but once done it only gets simpler from there. The main focus on the to-do list should be on getting a hang of the NCERT syllabus of NEET chemistry. .

Q1.  The catalyst iron, employed in the Haber’s process, contains molybdenum, the function of which is :

•   To increase the rate of combination of gases
•   To counterbalance for the presence of impurities in the gases
•   To act as a catalyst promoter and increase activity of catalyst
•   To make up for the adverse temperature and pressure conditions

Solution
Follow the concept of promoters.

Q2.  Which of the following statements is incorrect regarding physisorptions?

•   It occurs because of van der Waals’ forces
•   More easily liquefiable gases are adsorbed readily
•   Under high pressure it results into multimolecular layer on adsorbent surface
•   Enthalpy of adsorption (∆H_adsorption) is slow and positive

Solution
Adsorption is an exothermic process i.e., energy is released against van der Waals’ force of attraction (physisorptions).
Hence,∆H is always negative.

Q3.  Which acts as negative catalyst?

•   Lead tetraethyl as antiknock compound
•   Glycerol in decomposition of H₂O₂
•   Ethanol in oxidation of chloroform
•   All of the above

Solution
All are examples of negative catalysts.

Q4.  Lyophilic sols are more stable than lyophobic sols because the particles

•   Are positively charged
•   Are negatively charged
•   Are solvated
•   Repel each other

Solution
Lyophilic sols are more stable than lyophobic sols due to the fact that lyophilic colloids are extensively solvated.

Q5. Smoke (a negatively charged colloid) is an example of :

•   Gas dispersed in liquid
•   Gas dispersed in solid
•   Solid dispersed in gas
•   Solid dispersed in solid

Solution
  Smoke is carbon in air,negative aerosol.

Q6.  Which one of the following equation represents Freundlich adsorption isotherm?

•  
  
•  
  
• 
  
•  
  
  

Solution
Freundlich adsorption isotherm reaction is 

Q7. In which of the following, Tyndall effect is not observed?

•   Smoke
•   Emulsion
•   Sugar solution
•   Gold sol

Solution
Tyndall effect is not observed in sugar solution because it is a true homogeneous solution.

Q8. An example for autocatalysis is

•   Oxidation of NO to NO₂
•   Oxidation of SO₂ to SO₃
•   Decomposition of KCl₃ to KCl andO₂
•   Oxidation of oxalic acid by acidified KMnO₄

Solution
Autocatalysis is a process in which one of the product behaves as a catalyst.
e.g.,2KMnO₄+5H₂C₂O₄+3H₂SO₄→K₂SO₄+2MnSO₄+8H₂O+10CO₂
                                         (acts as catalyst)
The pink colour of KMnO₄dissappears slowly on reaction with oxalic acid, but the rate of disappearance of colour fastens after sometime due to the formation of MnSO₄ which acts as autocatalyst for the reaction.

Q9. A colloidion solution is one which contains :

•   Cellulose nitrate in a alcohol-ether
•   Cellulose in water
•   Sucrose in water
•   None of the above

Solution
The colloidion solution is used to prepare ultrafilters. It is a solution of 5% cellulose nitrate in alcohol-ether.

Q10.  Which statement is wrong?

•   Haber’s process of NH₃ requires iron as catalyst
•   Friedel-Crafts reaction requires anhydrous AlCl₃
•   Hydrogenation of oils requires iron as catalyst
•   Oxidation of SO₂ to SO₃ requires V₂O₅

Solution
Hydrogenation of oils requires Ni as catalyst.