Chapter 11

Assertion: Coagulation power of \(\mathrm{Al}^{3}\) is more than \(\mathrm{Na}\). Reason: Greater the valency of the flocculating ion added greater is its power incause precipitation (Hardy Schulze rule).

Assertion: Detergents with low CMC are more economical to use Reason: Cleansing action of detergents involves the formation of micelles. These are formed when the concentration of detergents becomes equal to CMC.

How many of these solutions are colloid here? Butter, Smoke, Pumic stone, milk, sugar solution, Aq solution of \(\mathrm{C}_{2} \mathrm{H}_{5}\) OH Ruby glass, cold cream, Paints.

How many of these metals are usally used as catalysts \(\mathrm{Pd}, \mathrm{Pt}, \mathrm{Ni}, \mathrm{Na} / \mathrm{liq} \cdot \mathrm{NH}_{3}\)

Alum is widely used to purify water since (a) it forms complex with clay particles (b) it coagulates the mud particles (c) it exchanges \(\mathrm{Ca}^{2+}\) and \(\mathrm{Mg}^{2+}\) ions present in hard water (d) its sulphate ion is water purifier

Which of the following characteristics is not correct for physical adsorption? \([\mathbf{2 0 0 3}]\) (a) adsorption on solids is reversible (b) adsorption is spontaneous (c) both enthalpy and entropy of adsorption are negative (d) adsorption increases with increase in temperature

Identify the correct statement regarding enzymes. [2004] (a) Enzymes are specific biological catalysts that cannot be poisoned (b) Enzymes are specific biological catalysts that possess well defined active sites

The volume of a colloidal particle, \(\mathrm{V}_{\mathrm{c}}\) as compared to the volume of a solute particle in a true solution \(\mathrm{V}\). could be [2005] (a) \(\sim 1\) (b) \(\sim 10^{23}\) (c) \(\sim 10^{-3}\) (d) \(\sim 10^{3}\)

The disperse phase in colloidal iron (III) hydroxide and colloidal gold is positively and negatively charged, respectively. which of the following statements is incorrect?(a) magnesium chloride solution coagulates, the gold sol more readily than the iron (III) hydroxide sol (b) sodium sulphate solution causes coagulation in both sols (c) mixing of the sols has no effect (d) coagulation in both sols can be brought about by electrophoresis

In Langmuir's model of adsorption of a gas on a solid surface (a) the rate of dissociation of adsorbed molecules from the surface does not depend on the surface covered (b) the adsorption at a single site on the surface may involve multiple molecules at the same time (c) the mass of gas striking a given area of surface is proportional to the pressure of the gas (d) the mass of gas striking a given area of surface is independent of the pressure of the gas

Gold numbers of protective colloids A, B, C and D are \(0.50,0.01,0.10\) and \(0.005\), respectively. The correct order of their protective powers is [2008] (a) \(\mathrm{D}<\mathrm{A}<\mathrm{C}<\mathrm{B}\) (b) \(\mathrm{C}<\mathrm{B}<\mathrm{D}<\mathrm{A}\) (c) \(\mathrm{A}<\mathrm{C}<\mathrm{B}<\mathrm{D}\) (d) \(\mathrm{B}<\mathrm{D}<\mathrm{A}<\mathrm{C}\)

Which of the following statement is incorrect regarding physissorptions? [2009] (a) More easily liquefiable gases are adsorbed readily. (b) Under high pressure it results into multi molecular layer on adsorbent surface. (c) Enthalpy of adsorption \(\left(\Delta \mathrm{H}_{\text {adsorption }}\right)\) is low and positive (d) It occurs because of van der Waal's forces.

According to Freundlich adsorption isotherm, which of the following is correct? (a) \(\frac{\mathrm{x}}{\mathrm{m}} \propto \mathrm{P}^{1 / \mathrm{n}}\) (b) \(\frac{x}{m} \propto P^{1}\) (c) \(\frac{x}{m} \propto P^{0}\) (d) All the above are correct for different ranges of pressure

The coagulating power of electrolytes having ions \(\mathrm{Na}^{+}, \mathrm{Al}^{3+}\) and \(\mathrm{Ba}^{2+}\) for arsenic sulphide sol increases in the order: (a) \(\mathrm{Ba}^{2+} \mathrm{Na}^{+}<\mathrm{Al}^{3+}\) (b) \(\mathrm{Al}^{3+}<\mathrm{Na}^{+} \mathrm{Ba}^{2+}\) (c) \(\mathrm{Al}^{3+}<\mathrm{Ba}^{2+}<\mathrm{Na}^{+}\) (d) \(\mathrm{Na}^{+}<\mathrm{Ba}^{2+}<\mathrm{Al}^{3}\)

\(3 \mathrm{~g}\) of activated charcoal was added to \(50 \mathrm{~mL}\) of acetic acid solution \((0.06 \mathrm{~N})\) in a flask. After an hou it was filtered and the strength of the filtrate was found to be \(0.042 \mathrm{~N}\). The amount of acetic acid adsorbed (per gram of charcoal) is (a) \(18 \mathrm{mg}\) (b) \(36 \mathrm{mg}\) (c) \(42 \mathrm{mg}\) (d) \(54 \mathrm{mg}\)

Match the catalysts to the correct processe Catalyst Process a. \(\mathrm{TiCl}_{3}\) (i) Wacker process b. \(\mathrm{PdCl}_{2}\) (ii) Ziegler-Natta polymerization c. \(\mathrm{CuCl}_{2}\) (iii) Contact process d. \(\mathrm{V}_{2} \mathrm{O}_{5}\) (iv) Deacon's process (a) a (iii), b (ii), c (iv), d (i) (b) a (ii), b (i), c (iv), d (iii) (c) a (ii), b (iii), c (iv), d (i) (d) a (iii), b (i), c (ii), d (iv)

For a liner plot of \(\log (\mathrm{x} / \mathrm{m})\) versus log \(\mathrm{p}\) in a Freundlich adsorption isotherm, which of the following statements is correct? (k and \(\mathrm{n}\) are constants) (a) \(1 / \mathrm{n}\) appears as the intercept (b) Only \(1 / \mathrm{n}\) appears as the slope (c) \(\log (1 / \mathrm{n})\) appears as the intercept (d) Both \(\mathrm{k}\) and \(1 / \mathrm{n}\) appear in the slope term.

The main oxides formed on comustion of \(\mathrm{Li}\), \(\mathrm{Na}\) and \(\mathrm{K}\) in excess of air are, respectively: [2016] (a) \(\mathrm{LiO}_{2}, \mathrm{Na}_{2} \mathrm{O}_{2}\) and \(\mathrm{K}_{2} \mathrm{O}\) (b) \(\mathrm{Li}_{2} \mathrm{O}_{2}, \mathrm{Na}_{2} \mathrm{O}_{2}\) and \(\mathrm{KO}_{2}\) (c) \(\mathrm{Li}_{2} \mathrm{O}, \mathrm{Na}_{2} \mathrm{O}_{2}\) and \(\mathrm{KO}_{2}\) (d) \(\mathrm{Li}_{2} \mathrm{O}, \mathrm{Na}_{2} \mathrm{O}\) and \(\mathrm{KO}_{2}\)