Surface-Chemistry-Quiz-4

Surface Chemistry Quiz-4

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 basic principal of cottrell’s precipitator is

•  Le-Chatelier’s principle
•  Peptisation
•  Neutralisation of charge on colloidal particles
•  Scattering of light

Solution
In Cottrell’s precipitator, the charged particles are attracted towards the walls of precipitator, here they lose their charge and coagulate. Hence, the basic principle of Cottrell’s precipitator is the neutralisation of charge on colloidal particles.

Q2.Which of the following is not an emulsion?

•  Butter
•  Ice cream
•  Milk
•  Clouds

Solution
Cloud is not an emulsion. Since, its dispersed phase is liquid and dispersion medium is gas. While emulsion is such type of a colloidal solution which has both the dispersed phase and medium in liquid state.

Q3.  The spontaneous outcome of internal liquid from gels is called :

•   Synerisis
•  Thixotropy
•  Swelling
•  None of these

Solution
It is the definition of synerisis, a property of gel.

Q4. Which is not true in case of catalyst?

•  The catalyst is unchanged chemically at the end of a reaction
•  The catalyst accelerates the reaction
•  In a reversible reaction, the catalyst alters the equilibrium position
•  A small amount of catalyst is often sufficient to bring about a large change in reaction

Solution
Catalyst does not alter the equilibrium constant.

Q5.When dilute aqueous solution of(excess) is added to KI solution, positively charged sol

of AgI is formed due to adsorption of of

•  
•  
•  
•  

Solution
 When aqueous solution ofis added to KI solution, positively charged sol of AgI is obtained due to the adsorption ofions on AgI molecules.

Q6. Which statement is wrong?

•  The catalyst does not alter the equilibrium of a reaction
•  Reaction with higher activation energy has higher rate constant
• In the endothermic reaction, the activation energy of the reaction is higher than that of heat of reaction
•  Half-life period of a first order reactions is independent of initial concentration

Solution

Q7.On adding 1 mL solution of 10% NaCl to 10 mL gold solution in the presence of 0.25 g of starch,

the coagulation is just prevented. Starch has the gold number equal to :

•  0.25
•  2.5
•  250
•  0.025

Solution
Gold no. is to be reported in mg.

Q8.Which of the following electrolytes is least effective in coagulation ferric hydroxide solution?

•  
•  
•  
•  

Solution
FeOH is a positively charged sol, thus coagulated by negative ion (anion). Smaller the charge on anion, smaller is its coagulating power or higher is its flocculation value.

Q9.In multimolecular colloidal solutions, atoms or molecules are held together by :

•  H-bonding 
•  van der waals’ forces
•  Ionic bonding
•  Covalent bonding

Solution
Strong intermolecular van der Waals’ forces operates among molecules.

Q10. A colloidal system in which gas bubbles are dispersed in a liquid is known as

•  Foam
•  Aerosol
•  Sol
•  Emulsion

Solution
A colloidal system in which gas bubbles are dispersed in a liquid is known as foam.