A scientist has a sample of metal that could be either cobalt or nickel. Which of
he following properties could be tested to classify the metal shape?
A. Mass
B. Density
C. Electrical conductivity
D. Reactivity with oxygen

Ithink the answer is d

Answer is: the equilibrium  shifts toward the reactants, to the left side of chemical reaction.it is because lead(ii) nitrate dissociates in water: pb(no₃)₂ → pb²⁺(aq) + 2no₃⁻(aq).according to lechatelier's principle, the position of equilibrium moves to counteract thechange (more lead cations, common ion), the position of equilibrium will move so that the concentration ofproducts decrease and concentration of reactants of chemical reaction increase.read more on -

Ch3cooh i think this is the answer