These are two distinct syntactic elements. On the one hand, we have the conditional nexus 'yes' and the adverb of denial 'no' : 'If you don't come now, you run out of food'. That is, they are two words that introduce a condition in negative mode. Instead, 'sino' is an adversarial conjunction that allows you to correct, specify or discard something previously said by something new: 'You should not mix chlorine with soap and water, but first clean with soap and then disinfect with a solution of chlorine water'. Here what Fundeu says : https : //www . fundeu. en/recommend/sino-si-no/
* Only one "like" per meaning and day, the more "likes" the meaning will appear higher in the list
