The mole fraction of KCl in the solution is 0.1051
calculation
mole fraction of KCl in solution = moles of KCl / total number of moles(moles of KCl +moles of H2O)
moles=mass/molar mass
mass of KCl=32.7g
molar mass of KCl= 39 +35.5
moles of KCl is therefore= 32.7g/74.5 g/mol=0.439 moles
find the moles of H2O= mass of H2O/molar mass
mass of H2O=100-32.7=67.3g
molar mass of H2O=( 1 x2) +16=18 g/mol
moles = 67.3/18 =3.739 moles
total moles=3.739+0.439=4.178 moles
mole fraction is therefore=0.439/4.178=0.1051
2.50 x 2/1 = 5 mol of Citric Acid
5 x (3+72+5+112) = 960g of Citric Acid
Answer: 960g of Citric Acid
yes substances Do react by mass
Answer: The statement conjugate base of hydrofluoric acid is weaker than that of acetic acid is most likely true.
Explanation:
A strong acid upon dissociation gives a weak conjugate base. This can also be said as stronger is the acid, weaker will be its conjugate base or vice-versa.
Hydrofluoric acid is a strong base as it dissociates completely when dissolved in water.
For example, 
The conjugate base is
which is a weak base.
Acetic acid is a weak acid as it dissociates partially when dissolved in water. So, the conjugate base of acetic acid is a strong base.

Thus, we can conclude that the statement conjugate base of hydrofluoric acid is weaker than that of acetic acid is most likely true.
Answer: 7.07 grams
Explanation:
To calculate the moles :


According to stoichiometry :
1 mole of
require 1 mole of 
Thus 0.052 moles of
will require=
of 
Thus
is the limiting reagent as it limits the formation of product and
is the excess reagent.
As 1 mole of
give = 1 mole of 
Thus 0.052 moles of
give =
of 
Mass of 
Thus 7.07 g of
will be produced from the given masses of both reactants.