Answer
A. It changes the rate, R
Explanation
When we change the concentration of the reactants in a chemical reaction, it affects the rate of reaction that happens in the process. Typically, the rate of reaction will decrease with time if the concentration of the reactants decreases because the reactants will be converted to products. Similarly, the rate of reaction will increase when the concentration of reactants are increased.
The question above is incomplete, the full question is given below:
What additional test would be needed to establish the exact position of hydrogen in the activity series of the following elements: magnesium, zinc, lead, copper and silver.
ANSWER
The position of hydrogen on a reactivity series can be determined by its ability to displace oxygen from the oxide of the metal concerned. If hydrogen is more reactive than a metal, it will displace oxygen from the metal oxide and reduce the metal oxide to its metal. If the metal is more reactive than hydrogen, hydrogen will not be able to reduce the metal oxide to its metal.
The smaller number is the number of protons, and the greater number is the mass.
The nuclear equation that describes the alpha decay of Polonium-210 can be written like this:
210/
84Po→206/82Pb+4/2 He