Tiêu đề DPP-8 SOLUTION.pdf ✅

CLASS : XIth SUBJECT : CHEMISTRY DATE : DPP No. : 8 1 (b) Gold number is defined as “the minimum amount of protective colloid in milligrams required to just prevent the coagulation of a 10 mL of a given gold sol, when 1 mL of a 10% solution of sodium chloride is added to it. 3 (c) Separation of the dispersed phase from the gel is known as syneresis 4 (b) Silica gel is a powerful adsorbent for moisture. 5 (a) The gold number of the given compounds is Gelatin - 0.005 to 0.1 Starch - 15 to 25 Albumin - 0.1 to 0.2 Blood or haemoglobin – 0.03 to 0.07 So, gelatin has the least gold number. 6 (c) Mixing the soles together can cause coagulation since the charges are neutralised. 8 (a) Larger is surface area, more is efficiency of catalyst. The surface area becomes more in finely powdered state, colloidal state or if surface is rough. 9 (d) Ionic surfactant molecules are preferentially adsorbed at the interfaces 11 (d) An emulsion is a dispersion of finely divided droplets in another liquid. Thus, it is a liquid, liquid colloidal system 12. (d) H + from weak acids or strong acids or enzyme’s invertase catalyse the hydrolysis of sugar. 13 (a) Rate = k [Reactant] or k = Ae ―Ea/RT Topic :- SURFACE CHEMISTRY Solutions
14 (d) —do— 15 (d) Fe is used in Haber’s process. 17 (c) A trade name for graphite-water sol. 18 (c) Active charcoal has greater surface area. ∴ it has more adsorption power. 19 (a) An aerosol is dispersion of solid or liquid in a gas. Smoke and dust are examples of aerosol. Aerosol is a type of colloidal system. 20 (c) When the reactants and catalyst are in the same phase, the catalysis is known as homogeneous. 2CO(g) + O2(g) NO(g) 2CO2(g) In this reaction both reactant and catalyst are in the gaseous phase.
ANSWER-KEY Q. 1 2 3 4 5 6 7 8 9 10 A. B B C B A C C A D B Q. 11 12 13 14 15 16 17 18 19 20 A. D D A D D C C C A C