34. Which of the following is not a solution? a Salt dissolved in water
b. Sand dissolved in water
c. Sugar dissolved in water
d. Oxygen dissolved in water

B==sand dissolved in water

b is wrong solution so because sand can't dissolve in water

Chemical weathering is the erosion or disintegration of rocks, building materials, etc., caused by chemical reactions (chiefly with water and substances dissolved in it) rather than by mechanical processes.

Explanation:

1. There are four types of chemical weathering: Reaction with water, Reaction with acid, Reaction with oxygen, and Reaction with organisms.

2. Chemical weathering occurs when water dissolves minerals in a rock, producing new compounds. This reaction is called hydrolysis. Hydrolysis occurs, for example, when water comes in contact with granite. Feldspar crystals inside the granite react chemically, forming clay minerals.