Can I install an iOS application on an Android smartphone?

NO. iOS is operating system and iPhone, iPad, iPod Touch are using iOS operating system. While Android smartphone are using Android Operating System. So iOS application (which extension is .ipa) are compiled for iOS. While Android can run .apk file because .apk file complied for Android OS. Same like you can not run windows application (.exe) file on android or iOS because .exe file compiled for Windows Operating System.

 

If you want to create an application for multi platform that is different question. And yes you can do it.

It is not possible to install an iOS app on android phone as iOS Applications are designed to work on iPhone OS(iOS).

In a normal case, you can't install an IOS application on an android phone, each OS has a different core than the other, but there are some tools those try to compile application from other OS, but till now they still weak and useless

i am not sure ... but till now u cant 

This will only be possible if the application has been developed as a cross platform / hybrid / or web application. There are some tools that "attempt" to automatically port the iOS code to android code, but they don't really do a clean job.

Not possible, Android platform only supports .apk format