Answer: Option (c) is the correct answer.
Explanation:
When an acid or base is added to a solution then any resistance by the solution in changing the pH of the solution is known as a buffer.
This is because a buffer has the ability to not get affected by the addition of small amounts of an acid or a base. As a result, it helps in maintaining the pH of the solution.
In the give case, when we add the HCl then more number of protons will dissociate. This causes the acetate to react with the protons and leads to the formation of acetic acid.
We know that acetic acid is a weak acid and it dissociates partially or feebly. Therefore, no change in pH will take place.
Thus, we can conclude that equation 
represents the chemical reaction that accounts for the fact that acid was added but there was no detectable change in pH.
Answer:
The rates of decay of radioactive elements
Explanation:
The age of a rock in years is called its absolute age. Geologists find absolute ages by measuring the amount of certain radioactive elements in the rock. When rocks are formed, small amounts of radioactive elements usually get included.
It gains or loses electrons to become like the Noble gases having 8 valence electrons to become the most stable.
Answer:
a. Change of state
Explanation:
Because you will see that the state has changed
1st and 4th options are suitable answers, as these 2 changes are not exactly physical changes as it cant return back to original form and as well as its not cooling, so I feel its 1st and 4th options
