In a distillation operation, the heat added to the boiler a) increases with increase in reflux ratio b) decreases with increase in reflux ratio c) remains unaltered with change in reflux ratio d) none of the above

a) increases with increase in reflux ratio

Explanation:

If we increase the reflux ratio, which can de defined as : L/D = Condesate back to column /distillate discarded from column, it means that we increase the amount of condensate back to column. So the reboiler load will increase and be maximum in case of Total reflux ratio. And as vapor load will be increased, diameter of column will be increased too.  

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."