Question

Question:A reducing solution breaks S-S bonds in proteins, whereas an oxidizing solution allows them to re-form. Discuss how such solutions might be used to carry out the curling of hair.

Short answer

Hair has proteins like keratin and melanin. By breaking the disulfide bonds in proteins, the reducing solutions soften the hair and straighten the curly hair. Oxidizing agents help to strengthen the hair.

Step-by-step solution

Anatomy of hair

Hair has proteins like keratin and melanine. The hydrogen bonding holds keratin together. If we apply heat or water on hair, the original shape of the hair changes. It regains after a few hours or if it comes contact with water or moisture.

Step 2: Reduction of hair

The shape of hair can be permanently changed chemically by altering the side groups in the hair. The bonds between the two sulfur atoms are broken through reduction using reducing solutions. Either the removal of oxygen or the addition of hydrogen occurs to the existing bonds to break these bonds. When these bonds are broken, the polypeptide chains change to a new shape. Hence, the straightening of the curly hair occurs.

Oxidation of hair

The broken disulfide bonds can be neutralized using oxidizing solutions like hydrogen peroxide. Thus, the hydrogen atoms are removed and the disulfide bonds are formed again. Hence, the straightened hair becomes curly again.