Question

what is observed when size of the finest gold sol particles increases in the gold sol

Answer 1

Tiny particles of gold (one hundred nanometers in diameter) are called goldnanoparticles, which are very useful. These goldnanoparticles produce vibrant colours. When these goldnanoparticles are suspended in solution solution appears red and as particle size increases solution turns pale blue, purple and colourless. Thesecolorsdepend on size, concentration of goldnanoparticles in solution.

 

The vibrant colours show gold nano particles interaction with light. These nano particles are efficient in absorbing specific frequencies and intensely scattering other frequencies. This property depends on size, shape, environment of gold nano particles. Hence individual gold paricles is red as it scatters red light more intensely but when many of nano particles mixed together then it appears blue or purple as it scatters blue or purple light more intensely. As gold nano particles do not scatter frequencies of other colours they will not appear in other colours.

b) Mutual precipitation- When two oppositely charged sols are mixed in equimolar proportions, they mutually neutralise their charge and both get coagulated.

Answer 2

a dissolution ,a large number of gold atoms agitate does the size of the finished gold soil particles increase in the gold a large number of atoms gold aggregate together to form a spices having size in colloidal range ( 1- 1000nm).