|Q1|>|Q2|
at a finite distance to the left ofQ1,the electric field is zero
|Q1|<|Q2|
at a finite distance to the right ofQ2,the electric field is zero
Number of Electric field lines emerging from Q1 are more than the number of lines terminating at Q2. So, Q1 is a positive charge of higher magnitude and Q2 is a negative charge of smaller magnitude. Hence, the point at which the electric field is zero is on the right of the negative charge Q2