212 ml of lead nitrate is required to prepare a dilute solution of 820.7 ml of lead nitrate.
Answer:
Option A.
Explanation:
Similar to Avagadro's law, there is another law termed as dilution law. As the product of volume and normality of the reactant is equal to the product of volume and normality of the product from the Avagadro's law. In dilution law, it will be as product of volume and concentration of the solute of the reactant is equal to the product of volume and concentration of solution.

So, as per the given question C1 = 5.45 M of lead nitrate and V1 has to be found. While C2 is 1.41 M of lead nitrate and V2 is 820.7 ml.
Then, 

So nearly 212 ml of lead nitrate is required to prepare a dilute solution of 820.7 ml of lead nitrate.
Elements which appear in the same column have similar properties (periodicity). For example, all of the elements in group XVII (17), the Halogens, all react in a similar fashion; they all like to attract one additional electron and form a -1 anion.
Answer:
A reaction is non-spontaneous at any temperature when the Gibbs free energy > 0.
Explanation:
There is a state function, that determines if a reaction is sponaneous or non spontaneous:
ΔG = Gibbs free energy
A reaction is non spontaneous when it does require energy to produce that reaction. It will be spontaneous, when the reaction does not require energy to be occured.
The formula is: ΔG = ΔH - T.ΔS
ΔH → Enthalpy → Energy gained or realeased as heat.
ΔH < 0 → <em>Exothermic reaction. Spontaneity is favored
</em>
T → Temperature
ΔS → Entropy → Degree of disorder of a system.
When the system has a considered disorder ΔS > 0, disorder increases.
When the system is more ordered, ΔS < 0, disorder decreases.
The reaction will be non spontaneous if, the enthalpy is positive (endothermic reaction) and the ΔS < 0 (disorder decreases). It will not occur if we do not give energy.
ΔG < 0 → Spontaneous reaction
ΔG > 0 → Non spontaneous reaction
ΔG = 0 → System in equilibrium