Which of the following is not an example of chemical weathering?
a. natural plant acid breaking down a rock
c. oxidation of metals
b. acid rain deteriorating a marble statue
d. ice wedging in rock

d. ice wedging in rock

Explanation:

Weathering is a natural process in which the rocks are broken down into pieces and sediments due to the effect of physical and chemical agents. Chemical weathering is a process by which the rocks are subjected to the treatment of chemical reaction like oxidation and hydrolysis which makes the physical structure of the rocks weak and causes the disintegration of rocks.

d. ice wedging in rock is the correct option this is because of the fact that it is the example of physical weathering instead of chemical weathering. In the case of ice wedging in rocks the water inside the rocks get solidified inside the rocks which leads to weakening of internal structure of rocks. Hence, results in weathering.