Colour of Colloids

Q. How to find out charge on colloidal particles

Q. Given below are two statements: one is labelled as Assertion A and other is labelled as Reason R.

Assertion A : Finest gold is red in colour, as the
size of the particles increases, it appears purple then blue and finally gold.
Reason R : The colour of the colloidal solution depends on the wavelength of light scattered by the dispersed particles.

In the light of the above statements, choose the most appropriate answer from the options given below.

Q. The colour of milk is white because

1. None of the above
2. Both the dispersed phase and the dispersion medium are colourless but the dispersed fat globules scatter all wavelengths equally
3. Both the dispersed phase and the dispersion medium are white and the dispersed fat globules scatter all wavelengths equally
4. The dispersed phase and the dispersion medium are made up of complement colours

Q.

Why sawdust is insoluble in water?

Q. Choose the correct statement regarding Tyndall effect:

1. Tynall effect is observed when the diameter of the dispersed particles is not much smaller than the wavelength of the light used
2. Tynall effect is observed when the refractive indices of the dispersed phase and the dispersion medium differ slightly in magnitude
3. The Tyndall effect is due to the fact that colloidal particles scatter light in only one directions in space
4. The scattering of light darken the path of beam in the colloidal dispersion

Q.

Mention the properties of colloidal solutions.

Q.

Rainwater stored in a tank contains sand grains, unfilterable clay particles, calcium carbonate, salt, pieces of paper and some air bubbles. Select from amongst these, an example each of a solvent, solute, colloidal and suspended particles.

Q.

Differentiate between a true solution, sol, and a suspension on the basis of

1. Particle size
2. Filterability
3. Stability size
4. Homogeneity

Q.

Which is more stable?

1. True Solution

2. Suspension

Q.

A suspension is a homogeneous mixture

1. True
2. False

Q. The colour of milk is white because

1. Both the dispersed phase and the dispersion medium are colourless but the dispersed fat globules scatter all wavelengths equally
2. Both the dispersed phase and the dispersion medium are white and the dispersed fat globules scatter all wavelengths equally
3. The dispersed phase and the dispersion medium are made up of complement colours
4. None of the above

Q.

List the constituents of milk. How can we prepare low fat milk?

Q.

Identify the colloid and true solution from the following:

1. Vinegar
2. Muddy water
3. Mist
4. Aluminium paint

Q.

The diameter of the colloidal particles may range from________.

1. ${10}^3\mathrm{m}\mathrm{to}{10}^{-3}\mathrm{m}$

2. ${10}^{-3}\mathrm{m}\mathrm{to}{10}^{-6}\mathrm{m}$

3. ${10}^{-6}\mathrm{m}\mathrm{to}{10}^{-9}\mathrm{m}$

4. ${10}^{-9}\mathrm{m}\mathrm{to}{10}^{-12}\mathrm{m}$

Q.

Which of the following will not show Tyndall effect?

1. Soap solution

2. Starch solution

3. Sugar solution

4. Gold sol

Q.

in which of the following the particles of solute can be separated by the process of filtration?

1. Solution

2. Colloid

3. Suspension

4. All the above

Q.

What kind of mixture will you get if 1 g of calcium carbonate is shaken with water? Name it.

Q.

Depending upon the nature of interaction between the dispersed phase and the dispersion medium, colloidal sols are divided in how many categories?

1. 4

2. 2

3. 1

4. 6

Q.

Which type of colloid has the particle size in between 1nm to 1000nm?

1. Multimolecular

2. Micromolecular

3. Associated

4. Macromolecular

Q.

Which electrolyte will precipitate a negatively charged colloids (As₂S₃ sol ) to a greater extend?

1. Ba²⁺

2. Fe²⁺

3. Na⁺

4. Fe³⁺

Q. What can be observed when sunlight is passed through a colloidal solution?

1. Adsorption
2. Coagulation
3. Tyndall effect
4. Brownian motion

Q.

Explain the differences between colloid and true solution.

Q.

Milk is an emulsion.

1. True
2. False

Q. The volume of a colloidal particle, $V_c$ as compared to volume of solute particle $V_s$ in a true solution could be:

1. $\frac{V_c}{V_s}\approx {10}^3$
2. $\frac{V_c}{V_s}\approx 10$
3. $\frac{V_c}{V_s}\approx {10}^{-3}$
4. $\frac{V_c}{V_s}\approx {10}^{22}$

Q. The size of the colloidal particles is in between:

1. ${10}^{-7}-{10}^{-9}cm$
2. ${10}^{-4}-{10}^{-7}cm$
3. ${10}^{-9}-{10}^{-11}cm$
4. ${10}^{-2}-{10}^{-3}cm$

Q.

What are colloids? Give two examples.

Q. The diameter of colloidal particles range from :

1. ${10}^{-6}m$ to ${10}^{-9}m$
2. ${10}^{-9}m$ to ${10}^{-12}m$
3. ${10}^{-3}m$ to ${10}^{-6}m$
4. ${10}^{3}m$ to ${10}^{-3}m$

Q.

In an aqua sol,

1. medium is alcohol

2. medium is water

3. medium is benzene

4. medium is ether

Q. In the colloidal state, the particle size ranges:

1. below $1$ nm
2. between $1$ nm to $100$ nm
3. more than $100$ nm
4. none of the above

Q. Particles having size between 1 and 1000 nm dispersed in a medium is called a:

1. colloid
2. none of the above
3. suspension
4. mixture