Chemistry 2024 JAMB Past Questions - Question 21: Common salt (NaCl) is used to pre­ serve foods. Which of the following properties can be used to determine its purity before use?

Correct Answer

B

Explanation

Generally, the purity of a solid substance can be determined using its melting point. A pure solid melts at a sharp temperature or over a narrow temperature. Impurities tend to low­er the melting point and broaden the melting range. By comparing the observed melting point of a sample with the known melting point of the pure substance, we can assess the purity of the sam­ple. If they match closely, the sample is likely pure; if there is a significant deviation, it suggests the presence of impurities.