Perl hash data check in IF condition not working

I'm new to perl and I'm working on perl code which use hashes. I wonder why I can't use hash data in a IF condition. For example,

Value of $post_val{'module'} is extension.

print "Module value: $post_val{'module'}\n";

if (chomp($post_val{'module'}) eq "extension") {
    print "correct...\n";
} else {
    print "wrong...\n";
}

I get following output,

Module value: extension

wrong...

What is going wrong here?