SURFACE AND INTERFACIAL PHENOMENON GPAT MCQs Part – 3

TOP 10 MCQ

1. The interfacial forces are related to the contact angle by [GPAT-2023 SHIFT-I]
(a) Nernst Equation
(b) Stokes Equation
(c) Young’s Equation
(d) Laplace Equation

2. In the Langmuir isotherm, following statements are true EXCEPT one [GPAT-2023 SHIFT-I]
(a) The layer of gas adsorbed on the solid adsorbent is one molecule thick
(b) Adsorbed layer is uniform all over adsorbent
(c) No desorption takes place when gas strikes solid surface
(d) No interaction between adjacent adsorbed molecules takes place

3. Which of the following surfactants is an ANIONIC surfactant [GPAT-2023 SHIFT-I]
(a) Lecithin
(b) Sorbitan esters
(c) Benzalkonium chloride
(d) Soaps

4. Which of the following emulsifiers has the highest HLB value [GPAT-2023 SHIFT-I]
(a) Span 80
(b) Acacia
(c) Tween 80
(d) Sodium lauryl sulfate

5. The addition of Monobasic Potassium Phosphate to suspended Bismuth Subnitrate particles causes A to B owing to C [GPAT-2023 SHIFT-II]
(a) A-negative zeta potential, B-decrease, C-adsorption of negatively charged phosphate anion
(b) A-positive zeta potential, B-increase, C-adsorption of negatively charged phosphate anion
(c) A-positive zeta potential, B-decrease, C-adsorption of negatively charged phosphate anion
(d) A-positive zeta potential, B-decrease, C-adsorption of positively charged hydrogen ion

6. The properties of solutions containing surface active agents change sharply over a narrow concentration range and are called as [GPAT-2021]
(a) Critical micelle concentration
(b) Ionic concentration
(c) Hydrogen ion concentration
(d) Surface tension

7. Which statements are correct for micelle formation [GPAT-2018]
[P] Micelles are dynamic structures continually formed and broken in solution
[Q] Typical micelle diameter is about 2–3 μm and visible under light microscope
[R] Micelle formation is a spontaneous process
[S] When surfactant concentration exceeds CMC, micelle number increases and free surfactant decreases
(a) P and Q
(b) P and R
(c) P and S
(d) R and S

8. The interfacial tension of Oleic acid against water at 20°C is [GPAT-2018]
(a) 15.6
(b) 52.3
(c) 428
(d) 8.51

9. Which of the following is an example of hemiester anionic surfactant for pharmaceutical emulsions [GPAT-2017]
(a) Sulfosuccinates
(b) Sarcosinates
(c) Taurates
(d) Lactylates

10. Surface tension is categorized as a/an factor [GPAT-2017]
(a) Capacity
(b) Intensive
(c) Extensive
(d) Tolerance

ANSWER KEY