Answer: Bubbles formed would be evidence that a chemical reaction took place when the solutions were combined.
Explanation:
As it is given that both 
and HCl chemically combine together leading to the formation of NaCl, water and carbon dioxide gas. As the gas is forming and its formation will also form bubbles into the solution.
This formation of bubbles actually indicate that a chemical reaction has taken place. As molecules of a gas are held by Vander waal forces so, this gas will readily escape into the atmosphere.
Thus, we can conclude that bubbles formed would be evidence that a chemical reaction took place when the solutions were combined.
Explanation:
1. Sedimentation and decantation cannot be used for all types of mixtures.
Decantation is a separation technique in which is used to separate immiscible liquids or mixtures containing liquid and solids within them.
In decantation, gravity is used to bring the denser materials to settle at the bottom.
For homogenous mixtures, it is not possible to use decantation. A solution of sugar and water will not decant.
2. Yes, mass of an object reduces the settling time of such object in a mixture.
The higher the mass, the faster the rate of settling. Also, as we know, mass is directly proportional to density. A body with a high density will settle faster in solution.
I believe the criteria responsible for deciding whether a heterogeneous mixture is a colloid or a suspension is whether the <span>particles remain suspended for an extended period of time. I hope it helps you.</span>
