The interface that cannot be obtained is 

1. Liquid-liquid

2. Solid-liquid

3. Liquid-gas

Colloids among the following that cannot be coagulated easily is -

a.  Lyophobic colloids

b.  Irreversible colloids

c. Reversible colloids

d.  Lyophilic colloids

1. (a, b)
2. (b, c)
3. (c, d)
4. (a, d)

The correct statements regarding the situation, when a Lyophilic sol is added to a Lyophobic sol, are-

a. Lyophobic sol is protected

b. Lyophilic sol is protected

c. Film of lyophilic sol is formed over lyophobic sol

d. Film of lyophobic sol is formed over lyophilic sol

1. (a, b)

2. (b, c)

3. (c, a)

4. (a, d)

Method by which lyophobic sol can be protected.

1.  By addition of oppositely charged sol.

2.  By addition of an electrolyte.

3.  By addition of lyophilic sol.

4.  By boiling.