I would like to know if violet bends the least or red I had read that violet bends the least. But most of the webpages state that red bends the least. I would like to know why it is so.
 A: You need to distinguish between two different optical phenomena of diffraction and refraction.
In diffraction the magnitude of the effect depends on the size of the object causing the diffraction relative to the wavelength of the light. As the object gets bigger than the wavelength the amount of diffraction gets small. This means as we reduce the wavelength of the light, i.e. go from red to violet, the diffraction decreases - violet light diffracts less than red light.
In refraction the light interacts with the electrons in the glass or whatever medium the light is passing through, and the amount of refraction depends on how strong the interaction is. In most transparent materials the interaction goes up with the energy of the photons in the light. Since shorter wavelengths have higher energies refraction increases as we go from red to violet, so violet light refracts more than red light.
If you're interested to know more about why refraction (usually) increases at shorter wavelengths there is an excellent but rather technical discussion in Why do prisms work (why is refraction frequency dependent)? and a less technical explanation in Why does the refractive index depend on wavelength?. There is a detailed discussion of the mechanism of diffraction in Why does wavelength affect diffraction?.
