V2Solutions IOS Developer interview questions

It was a four round process for iOS developer, mumbai. First was telephonic technical round followed by high level technical, managerial and HR rounds. Major technical questions were on objective C/cocoa , OOPs and version control followed by previous projects details. 1) Memory management ARC/non ARC, how to enable and disable it in xcode. 2) operation queues/ GCD/blocks in detail. Explain how to use these. 3) SOAP vs REST webservices. when to use which one. 4) singleton class. what will happen when you try to create second instance of singleton. 5) OOPs concepts abstraction, polymorphism, inheritence, encapsulation. How is it used in objective C. 6) delegates, notifications, protocols, categories in detail questioning. 8) MVC design pattern. 9) difference between distributed/centralised version control i.e git vs svn 10) unit testing related