Surface Chemistry Quiz-18
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. Which of the following curves do not
correspond to adsorption isotherms?
Solution
Q2. In Haber’s process for manufacture of ammonia,
the reaction is usually carried at about 500℃. If a temperature of
about 250℃ was used then
Solution
The optimum temperature for production of ammonia by Haber’s process is 500℃. If the temperature is lowered down then production of ammonia becomes slow down
The optimum temperature for production of ammonia by Haber’s process is 500℃. If the temperature is lowered down then production of ammonia becomes slow down
Q3. On addition of 1mL solution of 10% NaCl to
10mL gold solution in the presence of 0.025 g of starch, the
coagulation is prevented because starch has the following gold
numbers
Solution
Gold number of protective colloid is
“Colloid in milligrams which when added to 10 mL of gold solution just prevents its coagulation by 1mL of 10% NaCl solution.”
Gold number of protective colloid is
“Colloid in milligrams which when added to 10 mL of gold solution just prevents its coagulation by 1mL of 10% NaCl solution.”
The gold number of starch is 25, because it has very low
protective power.
Q4. A precipitate is changed to colloidal solution by the following process
Solution
(i)Dialysis is the method of separating particles of colloids from those of crystalloids by diffusion of mixture through perchament membrane.
(ii)Ultrafiltration is the method of separating particles of electrolyte from colloidal particle by filtering through ultrafilter paper.
(iii)Electrophoresis is the movement of colloidal particles under influence of electric field.
(iv) Peptization is a process of passing of precipitate into colloidal particle on addition of suitable electrolyte.
∴ Peptization is correct answer.
(i)Dialysis is the method of separating particles of colloids from those of crystalloids by diffusion of mixture through perchament membrane.
(ii)Ultrafiltration is the method of separating particles of electrolyte from colloidal particle by filtering through ultrafilter paper.
(iii)Electrophoresis is the movement of colloidal particles under influence of electric field.
(iv) Peptization is a process of passing of precipitate into colloidal particle on addition of suitable electrolyte.
∴ Peptization is correct answer.
Q5. Which of the following is true in respect of
adsorption?
Solution
Adsorption is an exothermic process and hence, ∆H is negative for adsorption. On the other hand the molecules of the adsorbate are held on the surface of the adsorbent and hence, they have lesser tendency to move about freely. In other words entropy decreases i.e.,∆Sis negative. According to Gibbs-Helmholtz equation, ∆G=∆H-T.∆S
Thus, for the process of adsorption to occur ∆G must be negative. Hence, for adsorption
Adsorption is an exothermic process and hence, ∆H is negative for adsorption. On the other hand the molecules of the adsorbate are held on the surface of the adsorbent and hence, they have lesser tendency to move about freely. In other words entropy decreases i.e.,∆Sis negative. According to Gibbs-Helmholtz equation, ∆G=∆H-T.∆S
Thus, for the process of adsorption to occur ∆G must be negative. Hence, for adsorption
Q6. A catalyst increases the rate of reaction
because it :
Solution
Catalyst lowers the activation energy or brings down the threshold energy barrier.
Catalyst lowers the activation energy or brings down the threshold energy barrier.
Q7. Milk can be preserved by adding a few drops of :
Solution
Formalin acts as preservative for milk.
Formalin acts as preservative for milk.
Q8. The phenomenon in which adsorption and absorption
takes place simultaneously is called:
Solution
Both process of adsorption and absorption taking place simultaneously are referred as Sorption.
Both process of adsorption and absorption taking place simultaneously are referred as Sorption.
Q9. The movement of colloidal particles towards their
respective electrodes in the presence of an electric field is
known as
Solution
Electrophoresis is movement of colloidal particles under the influence of electric field.
Electrophoresis is movement of colloidal particles under the influence of electric field.
Q10. Cod liver oil is
Solution
Emulsion is solution of liquid in liquid. Cod liver oil is emulsion.
Emulsion is solution of liquid in liquid. Cod liver oil is emulsion.
