Hi Gaurav,
I am not sure about the depth of your question. To answer your question in general (in my view), the main difference between a filter and an equalizer is that the first one performs only the function of attenuation, i.e. low-pass, high-pass, band-pass. However, the second one can also amplify the signal or set it to a certain level. In other words, an equalizer includes the features of a filter in it and has more advanced functionality.