Milady Cosmetology Practice Exam

What type of bond is easily broken by water and heat?

1. Disulfide Bond

2. Salt Bond

3. Hydrogen Bond

4. Peptide Bond

The correct answer is: Hydrogen Bond

The correct choice is hydrogen bond because these bonds are relatively weak and can be disrupted by the presence of water or by exposure to heat. Hydrogen bonds are formed when a hydrogen atom covalently bonded to a highly electronegative atom, such as oxygen or nitrogen, is attracted to another electronegative atom. This weak attraction allows hydrogen bonds to break easily under conditions such as increased temperature or when water is introduced, making it significant in processes like hair conditioning and chemical treatments. In contrast, disulfide and peptide bonds are much stronger covalent bonds. Disulfide bonds specifically require a chemical reaction, often involving a reducing agent, to be broken. Peptide bonds, which link amino acids in protein chains, are also stable under normal conditions and do not break easily without the influence of strong acids or bases. Salt bonds can also be disrupted by changes in pH or temperature but are generally more stable compared to hydrogen bonds. Understanding the nature of these bonds is crucial in cosmetology as it helps in selecting appropriate products and techniques for hair care.