A certain liquid X has a normal boiling point of 118.40 C and a boiling point elevation constant K,-240 С kg-mol-1. A solution is prepared by dissolving some benzamide (C, H,NO) in 150. g of X. This solution boils at 120.6 C. Calculate the mass of C, H,NO that was dissolved Be sure your answer is rounded to the correct number of significiant digits.

Answer : The mass of benzamide is, 0.166 grams

Explanation :

Formula used for Elevation in boiling point :

or,

where,

= boiling point of solution =

= boiling point of liquid X =

= boiling point constant  of liquid X =

m = molality

i = Van't Hoff factor = 1 (for non-electrolyte)

= mass of solute (benzamide ) = ?

= mass of solvent (liquid X) = 150 g

= molar mass of solute (benzamide ) = 121.14 g/mol

Now put all the given values in the above formula, we get:

Therefore, the mass of benzamide is, 0.166 grams