Cosmetology · Basic Chemistry of Products

Because the pH scale is logarithmic, a solution of pH 9 is how much more alkaline than a solution of pH 7?

Reviewed by Jordan Morley, Editorial Lead at 247SimpleTests. Written by the 247SimpleTests Editorial Team from the official source material cited on every question.

Correct answer

100 times as alkaline

A Twice as alkaline
B 10 times as alkaline
C The same
D 100 times as alkaline

Why this is the answer

Because the pH scale is logarithmic, each whole-number change represents a tenfold change. So a pH of 8 is 10 times more alkaline than pH 7, and a pH of 9 is 100 times (10 × 10) more alkaline than pH 7. This is why even a seemingly small pH number difference can mean a large chemical difference in how a product affects hair and skin. Understanding the logarithmic nature of the pH scale is emphasized in the scientific-concepts portion of the exam.

Source: Scientific Concepts — Logarithmic pH

Practice more questions

This question is from our Cosmetology Practice Tests practice test. Take the full practice test to test your knowledge across all Basic Chemistry of Products and other topics.

Take the Scientific Concepts practice test →

About this topic: Basic Chemistry of Products

Basic chemistry of products covers matter, elements and compounds, pH and the pH scale, acids and alkalis, oxidation and reduction, and how these ideas explain what shampoos, colours and chemical services actually do to the hair. This is one of 9 Scientific Concepts questions on basic chemistry of products, each with a full explanation on a single study page.

New to this exam? Our Cosmetology exam guide explains the format, scoring, and how to prepare.

Study materials on Amazon

Core textbook

As an Amazon Associate, CJ Affiliate, and AWIN publisher we earn from qualifying purchases. Links above are affiliate links. Full disclosure →

Because the pH scale is logarithmic, a solution of pH 9 is how much more alkaline than a solution of pH 7?

Why this is the answer

Practice more questions

About this topic: Basic Chemistry of Products

Related questions

On the pH scale, a value of 7 is considered:

The natural pH of healthy hair and skin is approximately:

What is the difference between a physical change and a chemical change in a substance?

An emulsion in cosmetics is best described as:

Study materials on Amazon

Milady Standard Cosmetology

State board exam study guides

Cosmetology practice test books