Washington Esthetician State Board Practice Exam

What property of hydrogen makes it useful in both antiseptic applications and as a hair-lightening agent?

1. Its divisibility

2. Its molecular weight

3. Its reactivity

4. Its electronegativity

The correct answer is: Its reactivity

The property of hydrogen that makes it particularly useful in both antiseptic applications and as a hair-lightening agent is its reactivity. Hydrogen is highly reactive, especially when in its diatomic molecular form (H2) or when part of compounds like hydrogen peroxide (H2O2). In antiseptic applications, its reactivity allows it to easily participate in chemical reactions that can kill bacteria and other pathogens. For example, hydrogen peroxide releases free radicals, which are capable of breaking down the cellular structure of microbes, making it effective for sanitizing wounds. When it comes to hair-lightening, the reactivity of hydrogen, especially in the form of hydrogen peroxide, plays a critical role as well. It acts as a bleaching agent by oxidizing the melanin in hair, effectively lightening its color. This combination of high reactivity in various chemical contexts not only enhances its efficacy in these roles but also highlights its versatility across different applications in esthetics. Other properties like divisibility, molecular weight, or electronegativity do not directly contribute to these specific uses of hydrogen.