$59.$ Daltons Law of Partial Pressures is significant in distillation because:

$-$ A$)$ It predicts the phase behavior of mixtures

$-$ B$)$ It describes the relationship between total pressure and solvent activity

$-$ C$)$ It allows for the calculation of individual component pressures in a mixture

$-$ D$)$ It determines the thermal conductivity of the vapor phase

$60.$ Differential distillation without reflux is characterized by:

$-$ A$)$ A high degree of separation per stage

$-$ B$)$ The need for multiple distillation columns

$-$ C$)$ A varying composition of distillate over time

$-$ D$)$ Constant composition of the residue

$61.$ The optimum reflux ratio in distillation:

$-$ A$)$ Minimizes the total number of stages required for separation

$-$ B$)$ Balances the energy and capital costs of the distillation process

$-$ C$)$ Is always lower than the minimum reflux ratio

$-$ D$)$ Is determined solely by the feed composition

$62.$ Multiple feeds in a distillation column are introduced to:

$-$ A$)$ Simplify the column operation

$-$ B$)$ Accommodate different boiling points of feeds

$-$ C$)$ Increase the flexibility of the separation process

$-$ D$)$ Reduce the column height