Answer 1) : Weak peaks
Explanation : When running a spectrum of a neat liquid, the problems that may arise using a low-viscosity liquid there will be weak peaks obtained and it will be difficult to interpret them. As there will be very thin path length between the salt plates to obtain the spectrum. The quality of the peaks will be low.
Answer 2) : Strong peaks
Explanation : When running a spectrum of a neat liquid, while using a viscous liquid the obtained peaks will be strong peaks. As the viscous liquid will enable to form a thick layer between the salt plates which will produce strong, intense and sharp peaks. This will be high resolved and clear peaks on the spectrum.