Question

This flask originally held some copper wire and a clear solution of nitric acid. The two substances reacted and produced a brown gas and a blue solution. This reaction cannot be reversed. Evidence of a chemical reaction is shown by A) ice forming. B) steam rising. C) the formation of a gas. D) a change in state from a solid to a liquid.

Answer 1

the answer is C) the formation of a gas because:
A) ice forming is a result of temparature change
B) steam rising is also a result of temparature change
D) a change in state can be reversed

Answer 2

Answer:The correct answer is option (C).

Explanation:

Evidence which tells us that chemical reaction has occurred:

• Formation of precipitate.
• Formation or evolution of the gas.
• Change in color of the solution mixture.
• Change in temperature of the solution mixture.

When the copper wire is held in clear solution of nitric acid brown colored gas was released with change in color of the solution. Both these observations means that chemical reaction has been taken place.

According to the option enlisted the correct answer is option (C).