Advertisements
Advertisements
Questions
Explain what is observed when an electrolyte NaCl is added to hydrated ferric oxide sol.
What happens when a solution of NaCl is added to a ferric hydroxide sol? Explain.
Advertisements
Solution
When NaCl is added to ferric oxide sol, it dissociates to give Na+ and Cl− ions. Particles of ferric oxide sol are positively charged. Thus, they get coagulated in the presence of negatively charged Cl− ions.
RELATED QUESTIONS
Out of MgCl2 and AlCl3, which one is more effective in causing coagulation of negatively charged sol and why?
Give reasons for the following observations: Leather gets hardened after tanning.
Explain what is observed when an electric current is passed through a colloidal sol?
Explain the terms Coagulation
What happens when an emulsion is centrifuged?
What happens when a lyophilic sol is added to a lyophobic sol?
(i) Lyophobic sol is protected.
(ii) Lyophilic sol is protected.
(iii) Film of lyophilic sol is formed over lyophobic sol.
(iv) Film of lyophobic sol is formed over lyophilic sol.
How does it become possible to cause artificial rain by spraying silver iodide on the clouds?
Why do we add alum to purify water?
What causes brownian motion in colloidal dispersion?
Match the statement given in Column I with the phenomenon given in Column II.
| Column I | Column II |
| (i) Dispersion medium moves in an electric field | (a) Osmosis |
| (ii) Solvent molecules pass through semi permeable membrane towards solvent side |
(b) Electrophoresis |
| (iii) Movement of charged colloidal particles under the influence of applied electric potential towards oppositely charged electrodes |
(c) Electroosmosis |
| (iv) Solvent molecules pass through semi permeable membranes towards solution side |
(d) Reverse osmosis |
Assertion: Colloidal solutions do not show brownian motion.
Reason: Brownian motion is responsible for stability of sols.
Assertion: Coagulation power of Al3+ is more than Na+.
Reason: Greater the valency of the flocculating ion added, greater is its power to cause precipitation (Hardy Schulze rule).
What is Gold number?
Gold number is associated with:-
The right option for the statement “Tyndall effect is exhibited by”, is:
Why a negatively charged sol is obtained when AgNO3 solution is added to KI solution?
Which of the following is a correct statement?
The conditions given below are in the context of observing Tyndall effect in colloidal solutions:
- The diameter of the colloidal particles is comparable to the wavelength of light used.
- The diameter of the colloidal particles is much smaller than the wavelength of light used.
- The diameter of the colloidal particles is much larger than the wavelength of light used.
- The refractive indices of the dispersed phase and the dispersion medium are comparable.
- The dispersed phase has a very different refractive index from the dispersion medium.
Choose the most appropriate conditions from the options given below:
