Why we only use the right hand to do the Anulom Vilom Pranayama (Alternate Nostril Breathing)?

I am excited to know why we only use our right hand to do the Anulom Vilom Pranayama ? Is there any scientific reason behind this?

you can use any hand

Patanjali defines Pranayama as the gap between inhalation and exhalation. Pranayama is usually considered to be the controlled inhalation and exhalation combined with retention, coming to your question, You can use any hand.