Answer : The correct option is, The concentration of the acid.
Explanation :
Molarity : Molarity is defined as the moles of solute present in one liter of the solution. Or it is defined as the concentration of solute present in one liter of solution.
The unit of molarity is, (M) i.e, mole/liter. It is also known as molar concentration.
Molarity of 0.01 M means, 0.01 concentration of the acid present in the solution.
Therefore, the 0.01 M refer to the concentration of the acid.
