Control rods are used<span> in </span>nuclear<span> reactors to </span>control<span> the fission rate of uranium and plutonium. They are composed of chemical elements such as boron, silver, indium and cadmium that are capable of absorbing many neutrons without themselves fissioning.</span>
Answer:
Equation 2, because K being more reactive, exchanges position with Pb in PbNO3.
Explanation:
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In this case, according to the given reactions, it is possible to realize that according to the reactivity series, since K is is group 1A of alkali metals, we infer it is by far more reactive than magnesium, for that reason last two choices can be easily discarded. Now, considering equation 2, it would be necessary to complete it to figure out the correct option:

Whereas it can be seen that potassium exchanges position with Pb according to the double displacement reaction; therefore, the correct answer is "Equation 2, because K being more reactive, exchanges position with Pb in PbNO3".
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The correct answer is D. Mixtures can be easily separated solutions cannot.
Answer is: the solubility of silver oxalate is <span>a. 1.4 × 10-4 m.
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<span>Chemical reaction
(dissociation) of silver oxalate in water:
Ag</span>₂C₂O₄(s) → 2Ag⁺(aq) + C₂O₄²⁻<span>(aq).
Ksp(Ag</span>₂C₂O₄) = [Ag⁺]²·[C₂O₄²⁻<span>].
[C</span>₂O₄²⁻] = x; solubility of oxalate ion.
[Ag⁺] = 2[C₂O₄²⁻<span>] = 2x
1.0·10</span>⁻¹¹ = (2x)² · x = 4x³.
x = ∛1.0·10⁻¹¹ ÷ 4.
x = 1.4·10⁻⁴ M.
They are both (polyatomic) ions.