I have a condo in Jersey City,NJ. On deed I am and one other.The mortgage is not on my name.Can I sell my part of condo which 50% ?

If your name is on the deed you may be able to sell your interest in the property.  It depends on the ownership that you have whether its as a tenant in common or as a joint tenant.  The deed will have to include the ownership interest of the other owner as well.