Photon is the smallest possible unit of electromagnetic energy that can be absorbed or emitted.
Ionization energy is the amount of energy required to remove the electron that is most loosely bound of an isolated gaseous atom to form a cation.
Electron affinity is the amount of energy released when an electron is added to a neutral atom or a molecule in a gaseous state to form negation ion.
The difference of ionization energy and electron affinity is ionization energy is the required energy to remove an electron from a neutral atom. Whereas, electron affinity is the energy change when a neutral atom attracts an electron to become a negative ion.
They are large molecules that increase the rate of biologically important reactions.
When PbSO₄ is added it dissociates as follows
PbSO₄ --> Pb²⁺ + SO₄²⁻
molar solubility is the number of moles of solute that can be dissolved in 1 L of solution
if molar solubility of PbSO₄ is X, then molar solubility of Pb²⁺ is X and SO₄²⁻ is X
the formula for ksp is as follows
ksp - solubility product constant
ksp = [Pb²⁺][SO₄²⁻]
ksp = X * X
ksp = X²
ksp = 1.82 x 10⁻⁸
X² = 1.82 x 10⁻⁸
X = 1.35 x 10⁻⁴ M
molar solubility of PbSO₄ is 1.35 x 10⁻⁴ M
answer is b.