It’s B. Substitution hope this helps
You did not provide possible answers, but one possible might be that the current atomic theory is so sound and plausible that there should not be anything that could change it in the near future.
We have Kc = 4.2 x 10^-2 (given but missing in the question)
and When the balanced equation for this reaction is:
PCl5(g) ↔ PCl3(g) + Cl2(g)
so, according to the Kc formula:
Kc = the concentration of products / the concentration of the reactants
so, to get the concentration of the reactants in equilibrium, the concentration of the products / the concentration of the reactants should equal the Kc value which is given in the question (missing in your question).
So by substitution in Kc formula:
Kc = [PCl3]*[Cl2] / [PCl5]
4.2 x 10^-2 = 0.18 * 0.25 /[PCl5]
∴[PCl5] = 0.18*0.25 / 4.2x10^-2 = 1.07
So the concentration of the reactants in equilibrim = 1.07
Answer:
Elements that belong to the <em>same </em><em>GROUP</em><em> </em>of the periodic table have the most similar chemical properties.
Explanation:
A GROUP in the periodic table is a column of elements with the same number of valence electrons. Since electrons are exchanged/shared during a chemical reaction, then elements with similar valence electrons, will react similarly. Thus elements belonging to the <em>same GROUP</em> are most similar in the way they react.
For example: Sodium and Lithium are group 1 elements while fluorine and chlorine are group 17 elements. In a reaction under normal conditions, Sodium and Lithium will both try to give up their single valence electron to form cations. In doing so they will react more similarly. On the other hand, Fluorine and Chlorine who are more inclined to accept a single electron to form cations react less like the group 1 elements and more like each other.
