Ohio Cosmetology License Exam — All Questions

In a salon, which level of decontamination is required for multi-use (reusable) implements such as metal shears and combs that have not touched blood or body fluids?

• a.Washing in hot soapy water, then air drying
• b.Cleaning, then full immersion in an EPA-registered disinfectant✓
• c.Autoclave sterilization before use on every client
• d.Wiping with a disinfectant wipe between clients

There are three levels of decontamination: sanitation (lowest, reduces germs), disinfection (kills most pathogens on hard nonporous surfaces), and sterilization (highest, destroys all microbial life). Multi-use implements must first be cleaned to remove visible debris and then fully immersed in an EPA-registered disinfectant for the manufacturer's stated contact time. Cleaning alone does not kill pathogens, and salons generally are not required to autoclave/sterilize implements that have not contacted blood.

What does an EPA registration on a salon disinfectant label indicate?

• a.It has FDA approval for use on human skin
• b.It is a plant-based cleaner containing no chemicals
• c.It kills the pathogens named on its label✓
• d.It works on contact, with no dwell time needed

Disinfectants used on hard, nonporous salon surfaces and implements must be EPA-registered. EPA registration means the manufacturer submitted efficacy data proving the product kills the pathogens named on the label (for example, bactericidal, virucidal, and fungicidal claims). The label also states the required contact (dwell) time, which must be followed for the product to work. The EPA regulates surface disinfectants; the FDA regulates products applied to the body.

MRSA (methicillin-resistant Staphylococcus aureus) is of particular concern in salons primarily because it is a bacterium that:

• a.Is resistant to many antibiotics and spreads by skin contact✓
• b.Spreads only by ingesting contaminated food or water
• c.Is a fungus that infects the nail plate
• d.Is killed by any household cleaning product

MRSA is a strain of Staphylococcus aureus bacteria that has become resistant to many antibiotics that once treated it, making infections harder to cure. It can spread through direct skin contact or by sharing contaminated implements and towels. This is exactly why strict cleaning and disinfection of implements between every client is essential in the salon.

If a client is accidentally cut and blood appears during a service, the correct procedure is to:

• a.Finish the service, then clean and disinfect the workstation
• b.Wipe the implement with alcohol and keep using it
• c.Apply an antiseptic and finish the service without gloves
• d.Stop, glove up, bandage the wound, and disinfect what touched blood✓

A blood spill requires following Universal (Standard) Precautions, which treat all blood and body fluids as potentially infectious. Stop the service, put on gloves, stop the bleeding and cover the wound, then clean and disinfect any implements or surfaces that contacted blood, and dispose of contaminated single-use materials in a properly sealed (often double-bagged) container. Implements exposed to blood should be disinfected with a product effective against bloodborne pathogens (HIV and hepatitis B/C).

Which layer of the hair shaft contains the melanin (pigment) and makes up most of the hair's strength and elasticity?

• a.The cuticle
• b.The cortex✓
• c.The medulla
• d.The follicle

The hair shaft has three layers. The cuticle is the tough outer layer of overlapping scales that protects the strand. The cortex is the thick middle layer that contains melanin (natural pigment) and the bonds responsible for most of the hair's strength, elasticity, and its response to chemical services like color and perms. The medulla is the soft, often absent core. The follicle is the skin structure that surrounds the root, not a layer of the shaft.

During a haircut, the term 'elevation' refers to:

• a.The direction in which the hair naturally grows
• b.The amount of tension applied while combing
• c.The angle at which a section is held away from the head✓
• d.The degree of shift from the section's natural fall line

Elevation (also called projection) is the angle at which a subsection of hair is lifted away from the head before it is cut. Zero elevation (held at 0 degrees, straight down) produces a blunt, one-length or heavier line; 90-degree elevation builds layers; and 180 degrees creates long, graduated layering. Controlling elevation, along with the cutting line/angle, is how a stylist creates weight, graduation, and layers.

The three phases of the hair growth cycle, in order, are:

• a.Anagen (growth), catagen (transition), telogen (rest)✓
• b.Telogen (growth), anagen (rest), catagen (transition)
• c.Catagen (growth), telogen (transition), anagen (rest)
• d.Anagen (rest), telogen (growth), catagen (shedding phase)

Hair grows in a repeating cycle of three phases. Anagen is the active growth phase, during which the hair is actively produced and can last several years. Catagen is the brief transition phase, when growth stops and the follicle begins to shrink. Telogen is the resting phase, at the end of which the hair sheds and a new anagen phase begins. Most scalp hair is in the anagen phase at any given time.

A client with very fine, thin hair wants more apparent volume. Which cutting approach generally helps create the illusion of fullness?

• a.Removing weight aggressively with heavy thinning throughout
• b.Layering with a blunt perimeter line✓
• c.Cutting all hair at zero elevation only, keeping maximum length
• d.Slide-cutting every section to remove as much density as possible

Fine or thin hair already lacks density, so aggressively thinning or removing weight makes it look even sparser. A blunt perimeter keeps the appearance of density at the ends, while controlled layering can build height and volume. The goal is to preserve and shape existing density, not strip it away. Matching the cutting technique to the client's hair type is a core styling fundamental.

On the pH scale, a product with a pH of 9 is:

• a.Neutral, the same as pure water
• b.Acidic
• c.Alkaline✓
• d.So acidic that it will dissolve hair

The pH scale runs from 0 to 14; 7 is neutral (pure water). Values below 7 are acidic, and values above 7 are alkaline (basic). A pH of 9 is alkaline. Alkaline products soften and swell the hair and raise the cuticle, which is why permanent color, lighteners, and alkaline (cold) waves are alkaline — they need the cuticle open to work. Acidic products (like many conditioners and toners) contract and smooth the cuticle. The scale is logarithmic, so each whole number is a tenfold change.

In permanent (oxidative) haircolor, what is the primary role of hydrogen peroxide (the developer)?

• a.It releases oxygen to develop the dye and lift pigment✓
• b.It seals the color molecules inside the cortex
• c.It acidifies the mixture to close the cuticle
• d.It swells the cuticle so the dye can enter

Permanent haircolor is an oxidation process. Hydrogen peroxide acts as the oxidizing agent (developer): it releases oxygen that both lightens (lifts) the hair's natural melanin and triggers the small color precursor molecules to combine into larger colored molecules trapped inside the cortex. Higher developer volumes (for example 20 vs. 10 volume) provide more oxygen and more lift. The alkaline ammonia in the color swells the cuticle so the developer and dyes can enter.

Which statement correctly contrasts a thioglycolate (acid/true-acid or cold-wave 'thio') perm with a hydroxide chemical hair relaxer?

• a.Both use exactly the same chemistry and are interchangeable on any hair
• b.Thio perms are permanent while hydroxide relaxers wash out in one shampoo
• c.Hydroxide relaxers can be neutralized back with thioglycolate and reused as a perm
• d.Thio perms are neutralized by re-oxidation; hydroxide relaxers are not✓

Ammonium thioglycolate (thio) waving breaks the hair's disulfide bonds by reduction; the hair is molded, then an oxidizing neutralizer rebuilds the bonds in the new shape. Hydroxide relaxers (sodium, potassium, lithium, or 'no-lye' guanidine hydroxide) straighten by a different, non-reversible chemical reaction (lanthionization) that permanently breaks disulfide bonds; they are stopped by thorough rinsing plus an acid-balanced neutralizing shampoo, not by an oxidizing neutralizer. Critically, thio and hydroxide chemistries are not compatible on the same hair and must never be layered without careful transition.

Before applying an oxidative (aniline-derivative) permanent haircolor, a predisposition test is performed to check for allergy. This test is known as the:

• a.Strand test
• b.Patch test✓
• c.Porosity test
• d.Elasticity test

A patch (predisposition) test is applied to the skin (behind the ear or inside the elbow) 24 to 48 hours before an aniline-derivative color service to detect an allergic reaction; a red, itchy, or swollen response is a positive reaction, and the service should not be performed. Do not confuse it with a strand test, which is done on a section of hair to preview the actual color result, timing, and the hair's condition — not to check for allergy.

The outermost layer of the skin, the one estheticians and cosmetologists work on most directly, is the:

• a.Epidermis✓
• b.Dermis
• c.Subcutaneous (adipose) layer
• d.Stratum papillare

The skin has three main layers. The epidermis is the thin outermost layer (its surface is the stratum corneum) and is where most surface skin-care and exfoliation work occurs. Beneath it is the dermis, the thicker living layer containing blood vessels, nerves, hair follicles, and sweat and oil glands. Deepest is the subcutaneous (adipose) layer of fatty tissue that provides insulation and contour.

A comedo (plural comedones), commonly seen in acne-prone skin, is best described as:

• a.A contagious viral growth on the skin surface
• b.A raised sac filled with clear fluid
• c.A follicle plugged with sebum and dead skin cells✓
• d.An area of increased pigmentation from sun exposure

A comedo is a follicle that has become plugged with sebum (oil) and dead keratinized cells. When the plug is exposed to air at the surface it oxidizes and darkens, forming an open comedo, or blackhead. When it is covered by skin it stays light and forms a closed comedo, or whitehead. Comedones are a hallmark of acne and are a disorder of the sebaceous (oil) glands, not an infection or a pigmentation change.

During a basic facial, why is a cleansing step performed before applying treatment products or a mask?

• a.To immediately close the pores so nothing can penetrate
• b.To remove makeup, oil, and surface debris✓
• c.Because treatment products work better on unwashed skin
• d.To strip away the skin's acid mantle before treatment

Cleansing is the foundational first step of a facial. Removing makeup, excess oil, sweat, and environmental debris leaves a clean surface so that subsequent steps — exfoliation, massage, treatment products, and masks — can perform as intended and penetrate more effectively. Cleansing does not permanently strip the skin's protective acid mantle; a well-formulated cleanser respects it.

The visible part of the nail that rests on the nail bed is called the nail plate. What is the term for the crescent-shaped, lighter area at the base of the nail?

• a.The free edge
• b.The eponychium
• c.The hyponychium
• d.The lunula✓

The lunula is the whitish, half-moon shape at the base of the nail; it is the visible part of the matrix, where nail cells are produced. The free edge is the part of the nail plate that extends past the fingertip. The eponychium is the living skin (cuticle area) at the base overlapping the plate, and the hyponychium is the skin beneath the free edge. Knowing nail anatomy helps a nail technician work safely without injuring living tissue.

A nail technician should understand the difference between a nail disorder and a nail disease. Which of the following can generally be serviced in the salon?

• a.A nail with signs of active infection, swelling, pus, or inflammation
• b.A noninfectious disorder such as ridges or discoloration✓
• c.A nail with a suspected fungal infection (onychomycosis)
• d.An inflamed, infected area around the nail (paronychia)

A general safety rule: if a nail or skin shows signs of infection or inflammation — redness, swelling, pus, heat, or a suspected fungal or bacterial infection — the client should be referred to a physician and the service should not be performed. Noninfectious cosmetic disorders (such as harmless ridges, minor discoloration, or brittleness) with no signs of infection can usually be worked on and improved cosmetically. When in doubt, do not service and refer out.

To prevent the spread of infection between clients during manicures and pedicures, a nail technician must:

• a.Reuse files and buffers if they still look clean
• b.Rinse metal implements under water only between clients
• c.Discard single-use items and clean and disinfect reusable ones✓
• d.Disinfect the pedicure foot basin once at day's end

Porous, single-use items such as nail files, buffers, and wooden pushers cannot be properly disinfected and must be discarded after one client. Reusable, nonporous metal implements must be cleaned to remove debris and then immersed in an EPA-registered disinfectant for the required contact time. Pedicure foot basins/spas are a known source of infection and must be cleaned and disinfected after every client, following the manufacturer's and regulatory procedures.

Which bone forms the forehead and the upper part of the eye sockets?

• a.The frontal bone✓
• b.The mandible
• c.The zygomatic bone
• d.The occipital bone

The frontal bone forms the forehead and the upper portion of the eye sockets. The mandible is the lower jaw (the only movable bone of the skull), the zygomatic bones are the cheekbones, and the occipital bone forms the back and lower part of the skull. Knowing head and facial bones helps cosmetologists understand facial shape and the underlying structure during facials and massage.

Trichology is the scientific study of:

• a.The nails and their disorders
• b.The bones of the face and skull
• c.The hair and its diseases and care✓
• d.The muscles of the neck and shoulders

Trichology is the branch of science that deals with the hair, its structure, functions, and diseases (from the Greek 'trichos,' meaning hair). Understanding trichology helps cosmetologists analyze scalp and hair conditions, recognize when a condition should be referred to a physician, and choose appropriate services. The study of the nails is onychology, and the study of the skin is dermatology.

During a scalp or facial massage the cosmetologist stimulates muscles and nerves. Which muscle covers the back of the neck and upper back and moves the head and shoulders?

• a.The orbicularis oculi
• b.The trapezius✓
• c.The frontalis
• d.The masseter

The trapezius is a large muscle covering the back of the neck and upper/middle back; it moves the shoulders and helps move the head. The orbicularis oculi is the ring muscle that closes the eye, the frontalis is the front portion of the epicranius that raises the eyebrows, and the masseter is a chewing muscle of the jaw. Awareness of these muscles guides safe, effective massage movements during scalp and facial services.

The seventh cranial nerve, which is the chief motor nerve of the face and is important during facial massage, is the:

• a.Trifacial (trigeminal) nerve
• b.Ulnar nerve
• c.Cervical nerve
• d.Facial nerve✓

The facial nerve is the seventh (7th) cranial nerve and is the chief motor nerve of the face; it controls the muscles of facial expression. The trifacial (trigeminal), the fifth cranial nerve, is the chief sensory nerve of the face and also serves the chewing muscles. The ulnar and cervical nerves serve the arm/hand and neck region respectively. Understanding facial nerves helps a cosmetologist locate motor points and perform beneficial massage.

An emulsion, such as a typical hair conditioner or hand cream, is best defined as:

• a.Immiscible liquids united by an emulsifier✓
• b.A pure element that cannot be broken down further
• c.A gas evenly dispersed through a liquid
• d.A solid completely dissolved in a liquid, as in a solution

An emulsion is a physical mixture of two or more immiscible (unblendable) substances, typically oil and water, held together by an emulsifier (surfactant) that keeps the droplets suspended. Common salon products are oil-in-water (O/W) or water-in-oil (W/O) emulsions. This is a physical mixture, not a pure element or a true solution of a solid dissolving completely; understanding emulsions helps explain how creams, lotions, and conditioners are formulated and behave.

In facial and scalp treatments that use electrotherapy, galvanic current differs from faradic current in that galvanic current is:

• a.A rapidly alternating current used mainly to produce heat
• b.A high-frequency current used to sanitize the skin with sparks
• c.A constant direct current that produces chemical reactions✓
• d.The same as household outlet current with no modification

Galvanic current is a constant, direct current (flowing in one direction) used to create chemical changes in the skin and to drive water-soluble products into or out of the skin (desincrustation and iontophoresis). Faradic current is an alternating, interrupted current used to cause muscle contractions (for toning). High-frequency (Tesla) current is a separate modality. Modalities in electrotherapy must be understood and used safely and only where permitted.

In the pH scale used throughout cosmetology chemistry, a change from pH 6 to pH 4 represents:

• a.The solution becoming more alkaline
• b.The solution becoming 100 times more acidic✓
• c.A small change of only two units
• d.The solution becoming twice as acidic

The pH scale is logarithmic, so each whole-number step is a tenfold change in acidity or alkalinity. Moving from pH 6 to pH 4 is a drop of two units, which means the solution becomes 10 x 10 = 100 times more acidic. Lower numbers are more acidic and higher numbers are more alkaline. This logarithmic nature is why small pH numbers on product labels represent large real differences in how a product affects the hair and skin.

A Safety Data Sheet (SDS), formerly called an MSDS, is an important salon document because it:

• a.Lists the retail price of each professional product
• b.Records which products each client has been serviced with
• c.Certifies the product as organic and free of hazards
• d.Lists a product's hazards, safe handling, and first-aid measures✓

A Safety Data Sheet (SDS) is supplied by the product manufacturer and provides critical safety information: the product's hazardous ingredients, associated health and physical hazards, safe handling and storage, personal protective equipment, and first-aid and emergency procedures. Salons should keep SDS documents accessible for the professional products they use. This is a worker-safety and right-to-know requirement, not a pricing or client-record document.

'Salon ecology' and good professional practice most directly refer to:

• a.Using only products that are marketed as natural
• b.The color scheme and decor chosen for the salon
• c.Keeping the salon clean, safe, and healthy✓
• d.The salon's marketing and client-retention strategy

In cosmetology, salon ecology refers to keeping the salon environment clean, safe, and healthy for both clients and staff. This includes proper cleaning and disinfection of tools and surfaces, good ventilation to manage fumes and dust, safe storage and handling of chemicals, and following infection-control procedures. Choosing natural-sounding products does not make a salon safe, and decor and marketing are separate business decisions.

Which of the following best reflects professional ethics for a cosmetologist?

• a.Honesty, confidentiality, and recommending only what the client needs✓
• b.Recommending the most expensive service regardless of the client's needs to maximize the ticket
• c.Sharing a client's personal information with other clients as conversation
• d.Guaranteeing medical cures for scalp or skin conditions

Professional ethics means acting with honesty and integrity: telling clients the truth about what a service can realistically achieve, keeping client information confidential, and recommending only the services and retail products the client actually needs rather than upselling for its own sake. Cosmetologists must also stay within their scope and never diagnose or promise to cure medical conditions, referring clients to a physician when appropriate.

Which level of decontamination destroys all microbial life, including bacterial spores?

• a.Sanitizing, which lowers the number of germs to a safer level only
• b.Disinfection, which kills most pathogens on hard nonporous surfaces
• c.Sterilization, the highest of the three decontamination levels✓
• d.Rinsing implements under warm running water after each client

Sterilization is the highest level of decontamination and is the only one that destroys every form of microbial life, including highly resistant bacterial spores. Sanitizing (cleaning) merely reduces the number of organisms present, and disinfection kills most pathogens on hard nonporous surfaces but cannot be relied on to destroy spores. Rinsing with water is not a level of decontamination at all; it removes some debris and nothing more.

What does cleaning (sanitizing) accomplish when a stylist washes a comb with soap and water?

• a.It removes visible debris and reduces germs, but does not kill most pathogens✓
• b.It destroys every bacterium, virus, and fungus living on the comb's outer surface
• c.It sterilizes the comb, so it may be reused with no further step needed
• d.It removes the need to immerse nonporous tools in an EPA-registered disinfectant

Cleaning is a mechanical process: soap, water, and friction lift oil, hair, product, and debris off the surface and physically wash organisms down the drain. That lowers the number of germs but does not kill the pathogens that remain. Cleaning is therefore the required first step, not a substitute for disinfection, and it certainly does not sterilize. A comb must still be immersed in an EPA-registered disinfectant before it touches another client.

A salon disinfectant is used exactly as its label directs. Which organisms may still survive on the implement?

• a.Common vegetative bacteria such as the staphylococci found on combs
• b.Bacterial spores, which resist most salon disinfectants✓
• c.Enveloped viruses named in the product's virucidal claim
• d.Fungi listed on a product that carries a fungicidal claim

Disinfection kills or inactivates most pathogens on hard nonporous surfaces, but bacterial spores are dormant, armored forms that survive drying, heat, and ordinary disinfectants. Only sterilization reliably destroys them. Organisms specifically named in the label's bactericidal, virucidal, and fungicidal claims are the ones the manufacturer proved the product kills when used at the labeled dilution and contact time, so those are not the survivors.

Ranked from the lowest level of decontamination to the highest, the three levels are:

• a.Disinfection first, then sanitation, and finally sterilization
• b.Sterilization first, then disinfection, and finally sanitation
• c.Sanitation, then sterilization, then disinfection
• d.Sanitation (cleaning), then disinfection, then sterilization✓

The three levels run from least to most effective: cleaning (sanitation) physically removes debris and reduces germs, disinfection kills most pathogens on hard nonporous surfaces, and sterilization destroys all microbial life including spores. The order matters in practice as well as on the exam, because an item must be cleaned before it is disinfected, and disinfection is the level the salon actually works at every day.

In which situation is sterilization, rather than disinfection, the required level of decontamination?

• a.For any instrument that penetrates the skin, which is sterilized or single-use and discarded✓
• b.For shears and clippers used on dry hair between two ordinary haircut clients
• c.For plastic capes and terry towels that go into the laundry at the end of a shift
• d.For countertops and shampoo bowls that are wiped down throughout the workday

Sterilization is reserved for instruments that break or penetrate the skin, because anything entering living tissue must carry no viable organisms at all; in most beauty settings such items are single-use and discarded instead. Ordinary salon tools, capes, towels, and surfaces do not penetrate skin, so cleaning followed by disinfection (or laundering, for linens) is the correct level for them.

Which salon practice is an example of sanitation, the lowest level of decontamination?

• a.Immersing metal shears in an EPA-registered disinfectant for the labeled contact time
• b.Autoclaving an instrument so that all microbial life, including spores, is destroyed
• c.Wiping a shampoo bowl with a product that carries a bactericidal efficacy claim
• d.Washing your hands with liquid soap and warm running water before a service✓

Sanitation reduces the number of organisms on a surface without killing most pathogens, and hand washing is its most familiar example. Immersing implements in an EPA-registered product and wiping a bowl with a disinfectant are both disinfection, the middle level. Running an instrument through an autoclave is sterilization, the highest level. Recognizing which activity belongs to which level is a routine exam question.

Why is disinfection, rather than sterilization, the working standard for most reusable salon implements?

• a.Because sterilizing equipment may legally be operated only by a licensed physician
• b.Because disinfectants destroy bacterial spores just as reliably as an autoclave does
• c.Because salon services are not meant to break the skin, so killing most pathogens suffices✓
• d.Because nearly all salon implements are porous and cannot be immersed in any liquid

Salon services are performed on intact skin, hair, and nails and are not intended to penetrate tissue, so the accepted standard of care is cleaning followed by disinfection with an EPA-registered product. Disinfectants do not match an autoclave against spores, salons are not barred from owning sterilizers, and most reusable implements are in fact nonporous metal or plastic that immerse perfectly well. Anything that does contact blood requires extra care or disposal.

A salon keeps combs in an ultraviolet 'sterilizer' cabinet. What is the correct understanding of this device?

• a.It sterilizes the implements inside, so cleaning and disinfection beforehand are unnecessary
• b.It is a storage container, and implements must still be cleaned and disinfected first✓
• c.It destroys bacterial spores on porous items such as emery boards and buffers
• d.It takes the place of the disinfectant solution used on shears between clients

Despite the name printed on the cabinet, an ultraviolet box is treated as a clean, closed storage container, not as a method of decontamination; most state boards do not accept UV light in place of cleaning and disinfecting. Implements must be cleaned, disinfected for the labeled contact time, dried, and only then stored in it. Nothing about the cabinet makes a porous item reusable, and porous single-use items are discarded regardless.

A salon disinfectant described as 'broad-spectrum' or hospital-level is one the label shows to be effective against:

• a.Only the bacteria that commonly live on the human skin, hair, and scalp
• b.Bacteria, viruses, and fungi, as spelled out in its efficacy claims✓
• c.Every organism in existence, including bacterial spores and parasites
• d.Household soils and odors rather than any specific microorganism

A broad-spectrum or hospital-level disinfectant carries efficacy claims covering bacteria, viruses, and fungi on hard nonporous surfaces, which is why it is the class of product salons use on implements and stations. It is not proof against every organism on earth, since even hospital-level products do not reliably kill bacterial spores. A cleaner that only lifts soils and odors is not a disinfectant at all and carries no kill claims.

A disinfectant label carries a tuberculocidal claim. What does that tell the cosmetologist?

• a.The product may be applied to a client's skin to prevent tuberculosis
• b.The product is safe to handle without gloves because it is nontoxic
• c.The product works instantly and has no contact time to observe
• d.The product kills the bacterium causing tuberculosis, an organism that is hard to kill✓

A tuberculocidal claim means the manufacturer demonstrated that the product kills Mycobacterium tuberculosis, an organism with a waxy cell wall that makes it unusually difficult to destroy; that is why the claim is used as a marker of potency. It says nothing about skin safety, and no disinfectant belongs on skin. Every disinfectant, tuberculocidal or not, still has a contact time on its label and still calls for gloves as the label and safety data sheet direct.

The 'contact time' (dwell time) stated on a disinfectant label refers to:

• a.How long the surface must stay visibly wet for the product to work✓
• b.How long the concentrate may be stored before it reaches its expiration date
• c.How long the diluted solution may be reused before replacement
• d.How long a technician may handle the product safely without wearing gloves

Contact time is the period the product must remain in continuous wet contact with the item or surface in order to achieve the kill claimed on the label; if it dries early, the surface must be rewetted. The correct universal statement is always the contact time stated on the manufacturer's label, because it differs from product to product. Shelf life, how often the solution is changed, and safe-handling limits are separate pieces of label information.

When diluting a concentrated disinfectant, the cosmetologist should:

• a.Add extra concentrate so the solution acts faster and lasts longer
• b.Estimate the dilution, since small differences do not change the result
• c.Measure and mix exactly as the label directs, every time✓
• d.Combine it with a household bleach product to broaden what it will kill

A disinfectant is proven effective only at the dilution printed on its label, so the concentrate and water must be measured, not estimated. Over-concentrating does not speed the kill; it wastes product, can corrode implements, and raises the exposure hazard to the user. Under-concentrating leaves a solution that may not kill what the label claims. Mixing two chemical products together is never acceptable, as some combinations release toxic gas.