Question 45

Table salt can be added to water to form a solution.

Table salt is a soluble substance that readily dissolves in water, creating a homogeneous mixture known as a solution. This process involves the dissociation of sodium and chloride ions in the water, making it an effective example of a solute.

A) Pencil lead

Pencil lead, primarily composed of graphite, does not dissolve in water. Instead, it may simply settle at the bottom of a container, failing to form a solution. Hence, this option is incorrect.

B) Candle wax

Candle wax is hydrophobic and does not mix with water. When added to water, it will float on the surface or form a separate layer, rather than creating a solution. Therefore, this option is incorrect.

C) Table salt

Table salt is an ionic compound that dissolves well in water, resulting in a solution. When added to water, the sodium and chloride ions separate and disperse uniformly, which is the key characteristic of a solution. This option is correct.

D) Iron filings

Iron filings are solid metal particles that do not dissolve in water. Similar to pencil lead, they will settle to the bottom and not form a solution. Thus, this option is incorrect.

Conclusion

Table salt is the only substance among the options provided that can dissolve in water to form a true solution. The other substances, including pencil lead, candle wax, and iron filings, do not exhibit solubility in water and therefore do not meet the criteria for forming a solution.