How does a solid catalyst enhance the rate of combination of gaseous molecules?
When gaseous molecules come in contact with the surface of a solid catalyst, a weak chemical bond is formed between the surface (catalyst) molecules and reactant (gas) molecules. Thus, concentration of reactant molecules increases at the surface.
The rate of reaction increases by adsorption of different molecules side by side facilitating the chemical reaction. Adsorption, being exothermic also help in increasing the rate of reaction (chemisorption increases with rise in temperature).
Do the vital functions of the body such as digestion get affected during fever? Explain your answer.
The optimum temperature range for enzymatic activity is 298-310 K, i.e., enzymes are inactive beyond this temperature range (high or low).
Thus, during fever (temperature $>310 \mathrm{~K}$ ) the activity of enzymes may be affected.
Method of formation of solution is given in Column I. Match it with the type of solution given in Column II.
| Column I | Column II | ||
|---|---|---|---|
| A. | Sulphur vapours passed through cold water. | 1. | Normal electrolyte solution |
| B. | Soap mixed with water above critical micelle concentration. | 2. | Molecular colloids |
| c. | White egg whipped with water. | 3. | Associated colloid |
| D. | Soap mixed with water below critical micelle concentration. | 4. | Macromolecular colloids |
A. $\rightarrow(2)$ B. $\rightarrow$ (3) C. $\rightarrow$ (4) D. $\rightarrow$ (1)
A. When sulphur vapours passed through cold water it leads to formation of molecular colloids.
B. When soap is mixed with water above critical micelle concentration it lead to formation of associated colloids.
C. White of egg whipped with water is an example of macromolecular colloids in which high molecular mass proteneous molecule acts as a colloidal particle.
D. Soap mixed with water below critical micelle concentration is known as normal electrolyte solution.
Match the statement given in Column I with the phenomenon given in Column II.
| Column I | Column II | ||
|---|---|---|---|
| A. | Dispersion medium moves in an electric field. | 1. | Osmosis |
| B. | Solvent molecules pass through semipermeable membrane towards solvent side. | 2. | Electorphoresis |
| c. | Movement of charged colloidal particles under the influence of applied electric potential towards oppositely charged electrodes. | 3. | Electroosmosis |
| D. | Solvent molecules pass through semipermeable membranes towards solution side. | 4. | Reverse-osmosis |
A. $\rightarrow(3)$ B. $\rightarrow$ (4) C. $\rightarrow$ (2) D. $\rightarrow$ (1)
A. Dispersion medium moves in an electric field is known as electroosmosis.
B. Solvent molecules pass through semipermeable membrane towards solvent side is known as reverse-osmosis.
C.Movement of charged colloidal particles under the influence of applied electric potential towards oppositely charge electrodes is known as electrophoresis.
D. Solvent molecules pass through semipermeable membranes towards solution side is known as osmosis.
Match the items given in Column I and Column II.
| Column I | Column II | ||
|---|---|---|---|
| A. | Protective colloid | 1. | $\mathrm{Fe Cl_3+NaOH}$ |
| B. | Liquid-liquid colloid | 2. | Lyophilic colloids |
| c. | Positively charged colloid | 3. | Emulsion |
| D. | Negatively charged colloid | 4. | $\mathrm{FeCl_3}$ + hot water |
A. $\rightarrow(2)$ B. $\rightarrow$ (3) C. $\rightarrow(4)$ D. $\rightarrow$ (1)
A. Lyophobic colloid (solvent hating colloid) are readily protected by small amount of electrolyte. These colloids are also stabilised by addition of lyophilic colloids which makes a protective layer around lyophobic sol. Hence, lyophilic sol are known as protective colloid.
B. Liquid-liquid colloid is also known as emulsion if they are partially miscible or immiscible liquids.
C. When $\mathrm{FeCl}_3$ is added to hot water it lead to the formation of positively charged colloid.
D. When NaOH is added to $\mathrm{FeCl}_3$ it lead to the formation of negatively charged colloid.