15. D is correct, exothermic reactions release heat
I am not sure about 16
Answer : (4) Chromatography
Explanation :
Chromatography : It is a separation technique of a mixture by passing it through a medium in which components travels at different rates.
There are many types of chromatography but this is paper chromatography.
Paper chromatography : It is used to separate the colored substances. In paper chromatography, water is the mobile phase and paper is the stationary phase. The mixture of components moves at different speeds through the stationary phase so that they can be separated.
In paper chromatography, several colors can be separated based on their solubility. The more soluble a color is, the more readily it will dissolve in mobile phase and farther it will travel.
A . A person Jumping represents an unbalanced force.
<u>Explanation:</u>
If equal amount of force applied on any object from both the directions, then the object will not move and so the force is a balanced force.
If an unequal amount of force on an object from both sides then the object will move in the opposite direction of the maximum force applied, so it is called as an unbalanced force.
- When the force is unbalanced then its velocity will change, so options C and D are omitted.
- In Option B the vase is sitting on a table, just kept so there is no action of any unbalanced force.
- But a person jumping represents an unbalanced force, since the person do not jump with constant velocity and it will vary.
