Answer:
D H2PO4– + HPO42–
Explanation:
The acid dissociation constant for
are
respectively.



The reason while option D is the best answer is that, the value of pKa for both
lies on either side of the desired pH of the buffer. This implies that one is slightly over and the other is slightly under.
Using Henderson-Hasselbach equation:

Answer:
Types of chemical weathering
1. Hydrolysis
2. Oxidation
3. Carbonation
4. Acid rain
5. Acids produced by lichens
Explanation:
Chemical weathering occurs when rocks undergo chemical reactions to form new minerals.
Hydrolysis : is when water dissolves minerals present in rocks forming new compounds.
Oxidation : is when oxygen reacts with rocks eg. rust formation
Carbonation : it uses an acid known as carbonic acid, it is important in the formation of many caves and sinkholes.