Answer:
9.28
Explanation:
pOH refers to a measure of hydroxide ions concentration. pOH tells about the alkalinity of a solution. If pOH is less than 7 then aqueous solutions are alkaline, acidic if pOH is greater than 7 and neutral if pOH is equal to 7.
Concentration of the hydroxide ions = 1.9 x 10-5 M
pH = 
pOH = 14 - pH
=14 - 4.72 = 9.28
Answer : The molar mass of the solute will be
87.90 g/mol.Explanation : We know the formula for elevation in boiling point, which is
Δt = i

m
given that, Δt = 0.357,

= 5.02 and mass of

= 40,
on substituting the value we get,
0.357 = (1) X (5.02) X (x/ 0.044), on solving we get x = 2.844 X

.
Now, 0.250/ 2.844 X

=
87.90 g/mol. which is the weight of unknown component.
Sorting is a method that could separate those materials
Nitrogen is diatomic which exists as N2. This is because of its small size and high electronegativity.
Phosphorus is tetra atomic which exists as P4.