Identity key on varchar column - T-SQL

I want to know if I can create an Identity (auto increment on a Varchar column. and how can I make it a primary key and create foreign key references on other table.

This is the code i have -

CREATE TABLE Questions(
    QuestionID int IDENTITY PRIMARY KEY, 
    QuestionNo as 'Q'+Cast(QuestionID as Varchar(10),       
    Question Varchar(200)
)

Is there a way I can make QuestionNo as Primary key and reference it in another table (say Answers (AnswerID, QuestionNo, AnswerText)?