Answer: the boiling point is = 137.325°C
Explanation:
From the formula: ∆Tb= Kb*m
From the question, Kb= 0.95, m= 27.5, T1= 111.2°C
Substitute into ∆Tb= Kb*m
∆Tb= 0.95*27.5= 26.125
∆Tb= T2-T1
Hence
T2- 111.2=26.125
T2= 26.125+ 111.2= 137.325°C
<u>Answer: </u>The correct statement is X is the effective nuclear charge, and it increases across a period.
<u>Explanation:</u>
We are given that:
X = number of protons − number of core electrons
Effective nuclear charge is defined as the actual nuclear charge (Z = number of protons) minus the screening effect caused by the electrons present between nucleus and valence electrons. These electrons are the core electrons.
The formula used for the calculation of effective nuclear charge given by Slater is:

where,
= effective nuclear charge
Z = atomic number or actual nuclear charge or number of protons
= Screening constant
The effective nuclear charge increases as we go from left to right in a period because nuclear charge increases with no effective increase in screening constant.
Hence, the correct answer is X is the effective nuclear charge, and it increases across a period.
<span>The number next to the simbol of the element ions (as a superscript) means the number of charges of the ion. For example N (+),, where (+) is a superscript means that the charge of the ion is 1+. S(2-), where (2-) is a superscript, means that the charge of the ion is (2-). OH (-), where (-) is a superscript, means that the charge of OH ion is (1-) . </span>
Fixed density
Particles move smoothly