Answer:
a)1.404 E-10 m^2/s
b)1.438 E-12 m^2/s
Explanation:
Diffusion Coefficients can be calculated at different temperatures taking into account the energy of the diffusive process, remember that this process takes place in the interstices of the solid, and gets with higher temperatures due to the higher kinetic energy of the particles.

a) For α-iron (BCC)

b) For γ-iron (FCC)

Answer:
Option B. Both have a pH less than 7, but H3PO4 has a lower pH than HCl
Explanation:
Those are acid, so the pH would be < 7.
H₃PO₄ is a weak acid with 3 dissociations
HCl is a strong acid.
pH depends on [H]⁺
H₃PO₄ → 3H⁺ + PO₄⁻³
HCl → H⁺ + Cl⁻
If both acid, have the same concentration, [H⁺]H₃PO₄ > [H⁺]HCl, that's why the pH from the phosphoric will be lower.
Answer:
(b) IE₂ of Ga > IE₂ of Ge
Explanation:
Electronic configuration of Ga is [Ar] 3d¹⁰4s²4p¹
Electronic configuration of Ge is [Ar] 3d¹⁰4s²4p²
After 1st ionisation , Ga becomes [Ar] 3d¹⁰4s² and becomes stable . Its
2 nd ionisation requires higher amount of ionisation energy. In case of Ge , there are 2 electrons in outermost orbital so it becomes stable after ionisation of 2 electrons.
Seven
Elements do not contain more than 7 electron shells.