Surface Chemistry - Result Question 27
28. The correct statement(s) about surface properties is(are)
(2017 Adv.)
(a) The critical temperatures of ethane and nitrogen are $563 K$ and $126 K$, respectively. The adsorption of ethane will be more than that of nitrogen of same amount of activated charcoal at a given temperature
(b) Cloud is an emulsion type of colloid in which liquid is dispersed phase and gas is dispersion medium
(c) Adsorption is accompanied by decrease in enthalpy and decrease in entropy of the system
(d) Brownian motion of colloidal particles does not depend on the size of the particles but depends on viscosity of the solution
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Answer:
Correct Answer: 28. (a, c)
Solution:
(a) Higher the critical temperature, greater the extent of adsorption.
(c) $\underset{\text { Adsorbent }}{P(s)}+\underset{\text { Adsorbate }}{Q(g)} \longrightarrow P Q(s)$
As gaseous adsorbate is adsorbed on solid surface, entropy decreases, $\Delta S<0$. Also formation of bond between $P$ and $Q$ results in release of energy, hence $\Delta H<0$.
BETA
