Can we rotate a mirror image by any angle to check if it is superimposable? [closed]

A molecule is chiral when it is different from its mirror image, and achiral if it is identical to its mirror image. To check if the mirror image is identical to the original object, we have to check if the two are super-imposable. Sometimes no rotation is necessary to show the molecule and mirror image are idential, and sometimes we need to rotate the mirror image, for example by 180°. This is so confusing. Can someone explain exactly what is to be done in simple words?

• Spatial perception is confusing, unless you're good at it naturally or have lots of practice. You are trying to check if you objects in possibility different orientations are the same. Are they the same? It's easiest if you can get them into the same orientation first.
– Zhe
Feb 23 '19 at 14:33
• If you need to rotate it, then rotate it. After all, no matter how much you rotate something, it is still the same thing; your left hand (hopefully) does not turn into your right hand if you turn it around. Feb 23 '19 at 14:34
• @orthocresol From your comment I am implying that it does not matter if I do not rotate or rotate 1° or 2° or 180° if I can fit it, it is achiral. Tell me if I am correct and thank you for responding. Feb 23 '19 at 14:39
• You can do what you want. If something is not superimposable it remains so. Your confusion is due to the fact that we must use projection to paper planes. Other is what symmetry of an object is. Feb 23 '19 at 15:37