Surface Chemistry Quiz-20

Surface Chemistry Quiz-20

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.  A catalyst is a substance which

•   Is always in the same phase as in the reactions
•   Alters the equilibrium in a reaction
•   Does not participate in the reaction but alters the rate of reaction
•   Participates in the reaction and provide an easier pathway for the same

Solution

Q2.  The fresh precipitate can be transformed in colloidal state by

•   Peptization
•   Coagulation
•   Diffusion
•   None of these

Solution
The conversion of freshly prepared suspension into colloid is known as peptisation and those substances which help for such a conversion are known as peptising agent.

Q3.  Blood contains :

•   Positively charged particles
•   Negatively charged particles
•   Neutral particles
•   Negatively as well as positively charged particles

Solution
Blood is negatively charged emulsion.

Q4.  Which of the following statement(s) is/are true?

•   Gelatin molecules (hydrophilic sol) are attracted to water molecules by London forces and hydrogen bonding
•   In hydrophobia sols, there is a lack of attraction between the dispersed phase and the continuous phase
•   Hydrophobia sols are basically unstable
•   All of the above

Solution

Q5. Rate of physical adsorption increase with

•   Decrease in surface area
•   Decrease in temperature
•   Decrease in pressure
•   Increase in temperature

Solution
  Physical adsorption decrease with increasing temperature or rate of physical adsorption increase with decreasing temperature.

Q6.  Conversion of milk into curd is made by the enzyme :

•   Diastase
•   Invertase
• Micoderma bacilli
•   Lactic bacilli

Solution

Q7. Which is correct in the case of van der Waals’ adsorption?

•   High temperature, low pressure
•   Low temperature, high pressure
•   Low temperature, low pressure
•   All of the above

Solution

Q8. Which of the following has maximum coagulation power with ferric hydroxide sol?

•   Cryolite
•   K₂C₂O₄
•   K₃[Fe(CN)]₆
•   K₄[Fe(CN)₆]

Solution
Ferric hydroxide sol is positively charged sol. It is coagulated by negative ions. Larger the charge on anion, larger is its coagulating power or smaller is its flocculation value. In K₄[Fe(CN)₆],the anion [Fe(CN)₆]^4- has highest charge,therefore K₄[Fe(CN)₆] is most effective in coagulating Fe(OH)₃ sol.

Q9. Which of the following is not a characteristic of chemisorption?

•   ∆H is the order of 400 kJ
•   Adsorption is irreversible
•   Adsorption may be multimolecular layer
•   Adsorption is specific

Solution
Activated charcoal is used for decolourizing and deodorizing sugar solution during the process of manufacture of sugar due to its adsorbing property.

Q10.  Ferric chloride is applied to stop bleeding because

•   Fe³⁺ions coagulate negatively charged blood solution
•   Fe³⁺ions coagulate positively charged blood solution
•   Cl^-ions coagulate positively charged blood solution
•   Cl^-ions coagulate negatively charged blood solution

Solution
Since ferric ions can coagulate negatively charged blood solution, therefore ferric chloride may be applied to stop bleeding