Answer: 9.98
Explanation:
1) The equation for the dissociation of pyridine is:
C₅H₅N₅(aq )+ H₂O(l) ⇄ C₅H₅NH⁺(aq) + OH⁻(aq)
2) Kb equation:
Kb = [C₅H₅NH⁺(aq)] [OH⁻(aq)] / [C₅H₅N₅(aq )]
Where:
[C₅H₅NH⁺(aq)] = [OH⁻(aq)] ← from the equilibrium reaction
[C₅H₅N₅(aq )] = 4.8 M ← from the statement
⇒ 1.9 × 10 ⁻⁹ = x² / 4.8 ⇒ x² = 9.12 × 10⁻⁹
⇒ x = 9.55 × 10⁻⁵ = [OH⁻(aq)]
3) pOH
pOH = - log [OH⁻(aq)] = 4.02
4) pOH + pH = 14
⇒ pH = 14 - 4.02 = 9.98
The periodic table of elements arranges all of the known chemical elements in an informative array. Elements are arranged from left to right and top to bottom in order of increasing atomic number. Order generally coincides with increasing atomic mass. The rows are called periods.
The effects of sinkholes vary based on where and how they were formed.
When naturally formed on land, they will change the topography of the surroundings, cause nothing but minor issues, if any issue at all.
When formed on highly populated areas, though, they can cause a lot of damage to humans and properties in the region. Damage caused to the base of a building might be a very serious problem.
Toxic chemicals can also come up through sinkholes.
Answer: Option (3) is the correct answer.
Explanation:
A molecule is polar when the net dipole moment of molecule is zero. When an electronegative atom is attached to an electropositive atom then the electronegative atom pulls the shared pair of electrons more towards itself.
As a result, the movement of electrons is more towards the electronegative atom and the dipole moment becomes zero. This will also induce partial positive and partial negative charge on electropositive and electronegative atom.
On the other hand, 
are covalent compounds and does not have a net zero dipole moment.
Thus, we can conclude that out of the given options 
represents a polar molecule.
