Q.1 One gm of charcoal absorbs 100 ml 0.5 M CH3COOH to form a monolayer, and there by 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 = 3.01 × 102 m2/gm [JEE’ 2003]
Ans. 5 × 10–19 m2
Q.2 20% surface sites have adsorbed N2. On heating N2 gas evolved from sites and were collected at 0.001 atm and 298 K in a container or volume is 2.46 cm3. Density of surface sites is 6.023 × 1014/cm2 and surface area is 1000 cm2, find out the no. of surface sites occupied per molecule of N2. [JEE 2005]
Q.3 Assertion : Micelles are formed by surfactant molecules above the critical miceller concentration (CMC).
Reason : The conductivity of a solution having surfactant molecules decreases sharply at the CMC.
Q.6 Silver (atomic weight = 108 g mol–1) has a density of 10.5 g cm–3. The number of silver atoms on a surface of area 10–12 m2 can be expressed in scientific notation as y × 10x. The value of x is – [JEE 2010]