Question

sky blue color aur purple se konsa colour banta hai​

Answer 1

If you mix blue and purple the colour you get will depend on what blue and what purple. This can be determined using a good colour wheel with 36 colours, not 12 colours as older colour wheels usually have. If you are using pigments then the closer your colours are around the wheel, the more pure colour the colour you will mix ; and the further apart the less pure, greyer, your colour will be.

For example if by blue you mean an ultramarine blue - slightly violet - and a dioxoine mauve you can create a pure blue-violet. However using a phthalo blue close to cyan - a blue-green - and a quin violet - a magenta - your colour will be less pure, greyer, even if you mix the same blue-violet hue.