Question 5.

On expanding the expression we get  

$1 - \log_a b + 1 - \log_b a$ or  $2 - \left( \log_a b + \frac{1}{\log_a b} \right)$

Now applying the property of AM ≥ GM, we get that  

$\frac{\log_a b + \frac{1}{\log_a b}}{2} \ge 1$ or  $\left( \log_a b + \frac{1}{\log_a b} \right) \ge 2$

Hence from here we can conclude that the expression will always be equal to $0$ or less than $0$. Hence any positive value is not possible. So $1$ is not possible.