Advertisements
Advertisements
Question
Which of the following statements are correct?
(i) Mixing two oppositely charged sols neutralises their charges and stabilises the colloid.
(ii) Presence of equal and similar charges on colloidal particles provides stability to the colloids.
(iii) Any amount of dispersed liquid can be added to emulsion without destabilising it.
(iv) Brownian movement stabilises sols.
Advertisements
Solution
(ii) Presence of equal and similar charges on colloidal particles provides stability to the colloids.
(iv) Brownian movement stabilises sols.
Explanation:
The presence of equal and similar charges on colloidal particles is largely responsible in providing stability to the colloidal solution, because the repulsive forces between charged particles having same charge prevent them from coalescing or aggregating when they come closer to one another. The Brownian movement has stirring effect which does not permit the particles to settle and thus, is responsible for the stability of sols.
APPEARS IN
RELATED QUESTIONS
Give reasons for the following observations:
Brownian movement provides stability to the colloidal solution.
Out of MgCl2 and AlCl3, which one is more effective in causing coagulation of negatively charged sol and why?
Out of BaCl2 and KCl, which one is more effective in causing coagulation of a negatively charged colloidal Sol? Give reason.
Explain the term Tyndall effect.
What happens when a freshly prepared precipitate of Fe(OH)3 is shaken with a small amount of FeCl3 solution?
What happens when persistent dialysis of a colloidal solution is carried out?
Answer the following question.
Why are medicines more effective in the colloidal state?
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.
Why do we add alum to purify water?
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).
Gold number of protective colloids A, Band Dare 0.50, 0.01 and 0.10 and 0.005. The correct order of their protecting power is
State the Hardy-Schulze rule.
Why a negatively charged sol is obtained when AgNO3 solution is added to KI solution?
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:
Coagulation value of the electrolytes AlCl3 and NaCl for As2S3 sol are 0.093 and 52 respectively. The No. of times AlCl3 has greater coagulating power than NaCl is ______.
In order to cause coagulation of 100 ml Arsenious sulphide sol 111.7 mg of 2 M NaCl solution is used, the coagulation value of NaCl will be ______.
6.84 g Al2(SO4)3 is needed to coagulate 2.5 L of As2S3 sol completely in 2.0 hrs. The coagulation value of Al2 (SO4)3 is ______.
