Question

why does solution of sodium chloride not show tyndall effect whereas the mixture of water and milk shows

Answer 1

Solutions of sodium chloride is a clear homologous solution while solution of milk and water is colloidal solutions which scatter the light passing through it and thus shows Tyndall effect

Answer 2

Solution of sodium chloride(salt solution) is known as true solutions because the particles of sodium chloride and water are mixed so that we cannot distinguish one from other.
Milk solution is called as colloidal .

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A Salt solution does not scatter a beam of light(tyndall effect)
Passing through it and render it's path visible because the particles
Of salt solution are extremely small in size. It is less than 1 nanometer.so such small particles cannot reflect light rays falling on them.
Whereas Milk solution particles are bigger enough ( in between 1nm to 100nm) to scatter the light passing through it.
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