Respuesta :
Answer:
B. H2CO3 and KHCO3
Explanation:
The buffer system is a system in which the solution deny for change in the ph level i.e. at the time when the acid is added to it. It can be made either in a weak acid and salt or can be a weak base and its salt. Now when the acid is added to a buffer so the ratio is not impacted due to which it does not change sufficient for pH level
As per the given options, the third one is correct as the H2CO3 denotes a weak acid and the KHCO3 represents the salt. And these two solution does not create any change in the level of pH
Therefore the option B is correct
