12th chemistry Chapter 5: Surface Chemistry
Welcome, 12th chemistry exam Important question based on CBSE board curriculum and corresponding to the recent 12 class Chemistry syllabus in text questions.
By rehearsing these Class 12 significant inquiries, understudies will actually want to rapidly survey every one of the thoughts shrouded in the part and plan for the Class 12 Yearly assessments as well as other selection tests like NEET and JEE.
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Why is it important to have a clean surface in surface studies?(Chemistry book)
Insurface studies, a clean surface is essential because it allows easier for desired species to adsorb. The air gases will not be available for the adsorption of desired gases if they cover the surface. Thus, in surface studies, a clean surface is vital.
What type of solutions are formed by dissolving different concentrations of soap In water?(Chemistry book)
Lower amounts of soap and water combine to form a typical electrolytic solution. After a particular concentration known as the critical micelle concentration, a colloidal solution variations.
Why is chemisorption referred to as activated adsorption?(Chemistry book)
Because there is a chemical bond between the reactants and the adsorbent, chemisorption is additionally referred to as activated adsorption. A high activation energy must be present for these chemical bonds to form.
Gelatin, which is a peptide, is added in ice creams. What can be its role?(Chemistry book)
Ice cream, becoming an emulsion, becomes stable and concentrated by Gelatin. By keeping the ice cream’s consistency, it aids in giving it a smooth texture.
What happens when gelatin is mixed with gold sol?(Chemistry book)
Gold sol is an unstable, lyophobic sol that repels solvents in order. Gelatin generates a lyophilic sol and functions as a protective colloid, which maintains the gold.
Can it cause artificial rain by spraying silver iodide on the clouds? Comment.(Chemistry book)
It is possible to spray silver iodide on clouds for producing artificial rain. Charges are carried by colloidal clouds. An electrolyte referred to silver iodide spray causes coagulation, which subsequently leads to rain.
What happens when an electric field is applied to a colloidal solution?(Chemistry book)
When an electric field is applied to a colloidal solution, the colloidal particles move towards the electrode. Positively charged particles move towards the cathode, while negatively charged particles move towards the anode.
Why do we add alum to purify water?(Chemistry book)
We add alum to water to make it cleaner because it coagulates colloidal impurities in the water, allowing them to settle and be removed by filtration or decantation. Thus, alum is added to water to purify it.
A colloid is formed by adding FeCl3 in excess of hot water. What will happen if excess sodium chloride is added to this colloid?(Chemistry book)
When added to hot water, FeCl3 forms hydrated iron oxide, which is a positively charged salt due to the absorption of Fe3+ ions. In NaCl, the negatively charged chloride ions coagulate the positively charged hydrated iron oxide. This leads to coagulation of the intestines.
What causes Brownian motion in colloidal solution?(Chemistry book)
Brownian movement is caused due to the collision between the molecules of the dispersion medium and chemical particles.
Why does leather get hardened after tanning?(Chemistry book)
Animal hair is colloidal. When hair with positively charged particles is soaked in tannin, which contains negatively charged colloidal particles, mutual coagulation occurs, resulting in hardening of the skin.
Why are medicines more effective in a colloidal state?(Chemistry book)
Medicines are more effective in colloids because colloids have a greater surface area. Thus, they are absorbed, absorbed and digested easily.
How do emulsifying agents stabilize the emulsion?(Chemistry book)
Emulsifiers, sometimes referred to as emulsifying agents, create a film between the medium and the suspended particles, which lowers the interfacial tension or surface energy between the two liquids that form the emulsion and stabilizes it.
Based on the Hardy-Schulze rule, explain why the coagulating power of phosphate is higher than chloride.(Chemistry book)
The valency of the coagulation ion determines the electrolyte’s coagulation properties, according to the Hardy-Schulze law. The amount of electrolyte needed in the atmosphere decreases as flocculating ions’ charge increases. The charge of phosphate ions is -3, whereas that of chloride ions is only -1. As a result, phosphate has a greater coagulation capacity than chloride.
How will you distinguish between the dispersed phase and dispersion medium in an emulsion?(Chemistry book)
An emulsion is diluted to some degree when a dispersion medium is added. However, if too much of the dispersed phase is added, it separates into its own layer. We raise the concentration of any dispersion medium or dispersed phase and observe the change to distinguish between the dispersed phase and dispersion medium.
Why does the bleeding stop by rubbing moist alum?(Chemistry book)
A colloidal solution is blood. Blood coagulation happens when moist alum is applied to the injured area. Therefore, coagulation—which halts the bleeding—is the primary cause.
How does the precipitation of colloidal smoke take place in the Cottrell precipitator?(Chemistry book)
Charged smoke particles travel through a chamber with charges on the other side of the smoke particles in the Cottrell precipitator. Particles of smoke precipitate after losing their charge on the plates.
What happens when dialysis Is prolonged?(Chemistry book)
The electrolyte traces that stabilize the colloids are completely eliminated as a result of excessive or prolonged dialysis, leaving the colloids unstable. Coagulation occurs as a result.
Why do physisorption and chemisorption behave differently with a temperature rise?(Chemistry book)
Weak van der Waals forces are involved in phytosisorption, and they get weaker as temperature rises. Like any other chemical reaction, chemisorption is facilitated by temperature increases and involves the creation of activation energy-based chemical bonds.
A delta is formed at the seawater and river water meeting point. Why?(Chemistry book)
While seawater has multiple electrolytes, river water is a colloidal clay solution. The electrolytes in the saltwater coagulate the colloidal solution of clay when river water meets seawater, causing the clay to deposit and creating the delta.
Do the body’s vital functions, such as digestion, get affected during fever? Explain your answer.(Chemistry book)
The enzymes required for the digestion process are biological catalysts that are active only during the specific temperature range, and at elevated temperatures, the activity of enzymes is hampered. The optimum temperature for enzyme action is 298-310 K. Normally, during the fever, the body temperature is elevated. Hence, it is expected that it can hamper enzyme activity during fever, and therefore digestion can also get affected.
Why is desorption important for a substance to act as a good catalyst?(Chemistry book)
Desorption is a crucial step in the process of removing products and making more room for the other reactant molecules to approach the surface and react after the reaction between the adsorbed reactants is complete. Therefore, for a material to function as a good catalyst, desorption is essential.
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