The Tyndall effect is a phenomenon observed when a beam of light is scattered by particles in a medium. It is typically exhibited by colloidal solutions. Let's examine why this is the case in comparison with other systems mentioned:
True Solutions: True solutions have solute particles, which are molecularly dispersed and far too small (less than 1 nm) to scatter light. Therefore, true solutions do not exhibit the Tyndall effect.
Suspensions: While suspensions have larger particles that can scatter light, these particles are heavy enough to eventually settle out due to gravity, thus suspensions are not stable and inconsistent in exhibiting the Tyndall effect.
Colloidal Solutions: Colloids contain particles of intermediate size (1-1000 nm) that are large enough to scatter light, but small enough to remain suspended in the medium without settling. This stability and particle size make colloidal solutions ideal for displaying the Tyndall effect, where the path of a light beam can be visibly observed due to scattered light.
Crystals: Crystals have a solid, ordered structure and do not allow for the scattering of light in the manner a liquid or gas medium does, hence they do not exhibit the Tyndall effect.
In conclusion, the correct answer is: Colloidal solutions.
‘X’ is a protecting colloid. The following data is obtained for preventing the coagulation of 10 mL of gold sol to which 1 mL of 10% NaCl is added. What is the gold number of ‘X’?