You can install it like that if you mark the mojoportal folder as an application in IIS.

But then your site url is going to not be a root level url, its going to be yourdomain/mojoportal/

Is that what you really want? If so why? What is it that makes you think its better to have an empty root folder? Seems not logical to me, I would want my site running as a root level url directly at domainname

And if you do decide to do that please name  the folder something besides mojoportal since having that in your url hurts the seo and page rank for this site.

I find that often that force of habit is because when people setup sites on their local machine they install everything under the default web site just because they don't really understand how to create additional sites and get them working, but most production web sites are going to be installed at the root level and it can be problematic when people try to move a site from a sub folder/virtual directory on their local machine to a root level site on production, its much better if your test environment has the same url pattern as production ie a root level site on your dev machine has the same url structure as a root level site in production even though the actual root url is different its ok because the structure is the same ie no folder segments in the urt. I wrote an article How to get Multiple IIS Web Sites working on your development machine to help people break out of the default web site mindset.

Of course if you're just experimenting you can install and configure things any way that works for you and if you find it easier to use a virtual directory so its easy to get rid of later that is fine but it isn't what I would recommend for an actual business production site.