How Nosql Databases have ACID( atomicity, consistency, isolation and durability) properties
NoSql can have the acid properties. Infact there are some nosql databases which follow the acid properties. CouchDB is one of such DB.
NoSQL is used to avoid schema based databases(to reduce developer’s overhead) which is directly contradicting ACID properties.
Yes, ACID is a basic thing for any transaction. They do not have a schema. And the biggest advantage is that there is no need of ALTER. And limitation is that there is no Foreign key and relational constraint.