PSI Barbering Practice Exam

What factor affects salt bonds in hair?

1. pH

2. Temperature

3. Humidity

4. Electric charge

The correct answer is: pH

The factor that affects salt bonds in hair is the pH level. Salt bonds are a type of bond formed between positively and negatively charged groups in the hair's protein structure, specifically in keratin. These bonds are sensitive to changes in pH because they rely on the ionic nature of the interactions between charged sites on the hair. When the pH of a solution changes, it can either increase or decrease the degree of ionization of these charged sites. At a lower pH (more acidic), the hydrogen ions can saturate the negatively charged groups, leading to the neutralization of those charges and consequently reducing the formation of salt bonds. Conversely, at a higher pH (more alkaline), there may be an increase in ionization, enhancing the opportunities for salt bonds to form. While temperature, humidity, and electric charge can influence the broader physical properties of hair and its overall integrity, they do not directly impact the chemical interactions that drive the formation and stability of salt bonds. Temperature can affect the overall flexibility and structure of hair but does not alter the ionic charge necessary for salt bonds. Humidity can affect water content, altering hair's texture and appearance but not the fundamental bonding mechanism. Electric charge may influence hair behavior in different contexts, yet it