Pure nitrobenzene freezes at 5.67 c. when 1.0g of ethanol (c2h6o) is mixed with

The freezing-point depression constant (Kf) of nitrobenzene is

Explanation:

Depression in freezing point is given by:

= Depression in freezing point

i= vant hoff factor = 1 (for non electrolyte nitrobenzene)

= freezing point constant = ?

m= molality

Weight of solvent = 20 g = 0.02 kg

mass of solute (ethanol) = 1.0 g

Molar mass of ethanol = 46 g/mol

Thus freezing-point depression constant (Kf) of nitrobenzene is

The question is incomplete, the complete question is:

Standardization of a Borax solution (Na2B4O7). A student titrates a 20.00 mL sample of an aqueous borax solution with 1.044 M H2SO4. It takes 2.63 mL of acid to reach the equivalence point. Knowing it takes 1 H2SO4 to neutralize 2 Na2B4O7, what was the concentration of this Borax solution?

The concentration of borax solution is 0.069 M.

Explanation:

To calculate the concentration of borax solution, the formula used is:

....(1)

where,

are the n-factor, concentration and volume of sulfuric acid

are the n-factor, concentration and volume of borax solution.

We are given:

Putting values in equation 1, we get:

Hence, the concentration of borax solution is 0.069 M.