Answer: Option (a) is the correct answer.
Explanation:
The given data is as follows.
= 4.19 
= 1.9 
Heat of vaporization (
) at 1 atm and
is 2259 kJ/kg
= 0
Therefore, calculate the enthalpy of water vapor at 1 atm and
as follows.
=
+
= 0 + 2259 kJ/kg
= 2259 kJ/kg
As the desired temperature is given
and effect of pressure is not considered. Hence, enthalpy of liquid water at 10 bar and
is calculated as follows.
= 
= 334.781 kJ/kg
Hence, enthalpy of water vapor at 10 bar and
is calculated as follows.

=
= 2410.81 kJ/kg
Therefore, calculate the latent heat of vaporization at 10 bar and
as follows.
=
= 2410.81 kJ/kg - 334.781 kJ/kg
= 2076.029 kJ/kg
or, = 2076 kJ/kg
Thus, we can conclude that at 10 bar and
latent heat of vaporization is 2076 kJ/kg.
Answer:
It has 140 neutrons because Mass number= No of protons + no of neutrons
The general formula for mass percent of a solution is:
% m/m = [grams of solute] / [grams of solution] * 100
And grams of solution = grams of solute + grams of solvent.
So, in our problem:
Solute = NaCl => mass of solute = 59.56 g
Solvent = H2O => mass of solvent = 165.1 g
=> mass of solution = 59.56 g + 165.1 g = 224.66 g
=> % m/m = [59.56 / 224.66] * 100 = 26.51 g (using four significant figures).
Answer: 26.51%