Free study questions · Cosmetology & Esthetics state board

Chemistry and pH practice questions

7 free chemistry and pH questions for the cosmetology and esthetics written exam (NIC's national theory test). Tap an answer to check yourself: each one comes with a short explanation and the source it's based on.

1. Question 1

   A product with a pH of 4.5 is:

   ASlightly acidicBNeutral, like waterCSlightly alkalineDStrongly alkaline
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   Answer: A. Slightly acidic

   On the pH scale of 0 to 14, 7 is neutral, below 7 is acidic and above 7 is alkaline. A pH of 4.5 is mildly acidic, close to the natural pH of skin and hair.

   NIC Cosmetology outline I: chemistry and pH

2. Question 2

   The pH scale is logarithmic. A solution with a pH of 10 is how much more alkaline than one with a pH of 9?

   A2 timesB10 timesC100 timesD1.5 times
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   Answer: B. 10 times

   Each step on the pH scale is a tenfold change. A pH of 10 is 10 times more alkaline than 9 and 100 times more alkaline than 8.

   NIC Cosmetology outline I: chemistry and pH

3. Question 3

   An emulsion is:

   AA pure substance made from a single type of atomBTwo unmixable liquids held together by an emulsifierCSolid particles that settle to the bottom unless shakenDA stable, uniform mixture such as salt dissolved in water
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   Answer: B. Two unmixable liquids held together by an emulsifier

   An emulsion, such as a lotion or cream, combines two immiscible liquids like oil and water with the help of an emulsifier. A solution is a stable, uniform mix, and a suspension separates on standing.

   NIC Cosmetology outline I: chemistry and pH

4. Question 4

   A surfactant molecule has a head that is attracted to water and a tail that is attracted to oil. The water-loving head is described as:

   ALipophilicBHydrophilicCHydrophobicDImmiscible
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   Answer: B. Hydrophilic

   Hydrophilic means water-loving and lipophilic means oil-loving. A surfactant’s two ends let it lift oil and dirt into the rinse water, which is how shampoos and cleansers work.

   NIC Cosmetology outline I: chemistry and pH

5. Question 5

   Pure water has a pH of about:

   A14.0B7.0C4.5D9.5
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   Answer: B. 7.0

   Pure water is neutral, with a pH of 7, because it has equal amounts of hydrogen and hydroxide ions. Tap water varies a little with its minerals.

   NIC Cosmetology outline I: chemistry and pH

6. Question 6

   Alkaline solutions affect the hair by:

   ASwelling the hair and raising the cuticleBHardening the cortex and adding shineCDissolving the medulla and adding weightDShrinking the hair and sealing the cuticle
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   Answer: A. Swelling the hair and raising the cuticle

   Alkaline products soften and swell the hair and lift the cuticle so chemicals can reach the cortex. Acidic products do the opposite, contracting the hair and closing the cuticle.

   NIC Cosmetology outline I: chemistry and pH

7. Question 7

   Acid-balanced products are used after alkaline chemical services mainly to:

   ABreak disulfide bonds for a permanent waveBStrip leftover oils from the scalpCClose the cuticle and restore the hair’s natural pHDOpen the cuticle so the hair absorbs more color
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   Answer: C. Close the cuticle and restore the hair’s natural pH

   Hair and skin are naturally slightly acidic. Acid-balanced rinses and conditioners help close the cuticle and return hair to its normal pH after alkaline services.

   NIC Cosmetology outline I: chemistry and pH

These are original practice questions written from public sources such as the CDC, OSHA, the FDA and NIC's published exam outlines, in the same multiple-choice format as the real exam. NIC doesn't publish its live exam questions.