Which of the following is an example of a physical change ?
A) Zinc metal is added to hydrochloric acid and a gas is released.
B) Concentrated hydrochloric acid is diluted with water.
C) Acid rain causes the decomposition of a marble statue.
D) Hydrochloric acid is neutralized by a base to produce a salt and water.
B is the intended answer.
A physical change refers to a change in the physical properties of a substance without altering its chemical composition. Let's go through the options and identify which one is a physical change.
A) Zinc metal is added to hydrochloric acid and a gas is released.
In this scenario, a gas is being released as a result of a chemical reaction between the zinc metal and hydrochloric acid. This gas production indicates a chemical change, not a physical change.
B) Concentrated hydrochloric acid is diluted with water.
Dilution of concentrated hydrochloric acid with water is a physical change. It does not involve any chemical reactions or alteration of the chemical composition of the acid. Only the concentration of the acid is being changed.
C) Acid rain causes the decomposition of a marble statue.
The decomposition of a marble statue due to acid rain is also a chemical change. The acid rain reacts with the marble, causing a chemical reaction that breaks down the structure of the marble. It results in a change in both physical and chemical properties.
D) Hydrochloric acid is neutralized by a base to produce a salt and water.
Neutralization of hydrochloric acid with a base to produce a salt and water is a chemical change. It involves a reaction between the acid and the base, resulting in the formation of new substances.
Based on the explanations above, option B) Concentrated hydrochloric acid is diluted with water is the example of a physical change, as it involves only a change in physical properties without any chemical reaction or alteration of chemical composition.