questions of surface chemistry in last ten years IIT question papers

Hi Maulik,

1. Rate of physisorption increases with

    a. decrease in temp.

    b. increase in temp.

    c. decrease in pressure

    d. decrease ion surface area.(2003)

2. Adsorption of gases on solid surface is generally exothermic because

     a.enthalpy is positive

     b.entropy decreases

     c.entropy increases

     d.free energy increases. (2004)

3. Lyophillic sols are

     a. irreversible sols

     b.they are prepared from inorganic compound

     c.coagulated by adding electrolytes

     d.self-stabilizing.(2005)

4. Among the following, the surfactant that will form micelles in aqueous solution at the lowest molar concentration at ambient conditions is

     a. CH₃(CH₂)₁₅N⁺(CH₃)₃Br-

     b. CH₃(CH₂)₁₁OSO₃^-Na⁺

     c. CH₃(CH₂)₆COO^-Na⁺

     d. CH₃(CH₂)₁₁N⁺(CH₃)₃Br-.(2008)

5. 1g of charcoal adsorbs 100 ml 0.5M CH3COOH to form a monolayer and therby the molarity of CH3COOH      reduces to 0.49. Calculate the surface area of the charcoal adsorbed by each molecule of acetic acid. Surface area of charcoal is 300 m²/g.(2003)

6. statement 1: Micelles are formed by surfactant molecules above the critical micellar concentration(CMC).

    statement 2: The conductivity of a solution having surfactant molecules decreases sharply at the CMC.(2007)