Why do some liquids form a convex surface when placed in a narrow test tube while others form a concave surface​

away from the curb

explanation:

the wheels would then hit the curb if it started to rolling, decreasing the chance of an accident.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

the answer is barium and copper bromide