Answer the following questions:
A teacher divides the class into four groups A, B, C, D and provides each group with a different sample. group A is given a few crystals of copper sulphate, group B is given one spatula full of copper sulphate, group C is given chalk powder or wheat flour, and group D is given a few drops of milk or ink. Each group adds the given sample to water and stirs the mixture properly using a glass rod. Based on the observations made after stirring answer the following questions.
1. Between Group A and Group B, which group forms a concentrated solution?
2. Which group of mixtures is unstable and whose particles settle down on standing?
3. The mixture in Group D that contains milk or ink mixed with water is an example of which type of mixture?