7 Common Household Chemical Reactions—And How to Avoid Them

bottle of bleach

The Spruce / Candace Madonna

Chemical reactions are happening all of the time in our homes. Some are wonderful—without the reaction of yeast with sugars, there would be no leavened bread or wine. The enzyme rennet reacts with milk or cream to form the curds that become cheese. And, without the Maillard reaction that occurs when sugars and denatured proteins begin to break down and reconfigure when exposed to heat, we would have no crispy, browned meats.

But there are other chemical interactions that can produce out-of-control reactions, minor problems or deadly ones. Learn what happens when common chemicals are mixed or handled improperly and how to avoid toxic reactions.

Precautions to Take

There are a few general things to keep in mind when you're working with common household chemicals.

  • Always read product labels. Even common household cooking and cleaning products may pose risks if they are mixed with other chemicals.
  • Always store chemicals properly and separately from one another.
  • Never mix cleaning chemicals, pesticides, or paint-stripping products unless instructed by product labels.
  • Always dispose of hazardous chemicals properly following the guidelines of your local waste management agency.
  • 01 of 07

    Baking Soda (Sodium Bicarbonate) and Acids

    When baking soda (sodium bicarbonate) is combined with any type of vinegar (dilute acetic acid) or citrus juice (citric acid), carbon dioxide gas and sodium acetate form and produce a pretty spectacular bubbling reaction. Luckily, it is non-toxic to the lungs and it does make a pretty impressive volcanic flow for a science project.

    When used for cleaning, the bubbles from baking soda and acid do little to help lift soil from surfaces. It is more effective to use the products separately.

  • 02 of 07

    Bleach (Sodium hypochlorite) and Acids

    When chlorine bleach is mixed with vinegar, lemon juice, or any acid, deadly chlorine gas forms. This is the same gas that is used in warfare to attack the skin with chemical burns and to irritate the respiratory system. Small concentrations will make you cough and irritate your eyes, mouth, and mucous membranes. Longer exposures and higher concentrations are deadly unless you can get to fresh air.

    If a reaction occurs, you should act immediately.

    • Open a window to bring in fresh air and turn on an exhaust fan to ventilate the air.
    • Leave the area at once to allow the gas to dissipate.
    • If you feel faint or ill, call for assistance.
    • Do not reenter the area until you are sure the space is safe.

    Take time to read labels on toilet bowl cleaners. Many of these cleaners contain acids and should never be mixed with bleach.

  • 03 of 07

    Bleach (Sodium hypochlorite) and Ammonia

    Chlorine bleach and liquid ammonia are two powerful and common household cleaners that should never be used together. When combined, they react to form chloramine vapors or deadly hydrazine.

    Depending upon their intensity, chloramine vapors can move from irritation of the eyes and respiratory system to internal organ damage. If the mixture is heavy with ammonia, hydrazine is produced. It is toxic and explosive and can cause a painful death.

  • 04 of 07

    Bleach (Sodium hypochlorite) and Isopropyl Alcohol

    When the sodium hypochlorite in chlorine bleach reacts with isopropyl (rubbing) alcohol, chloroform gas is produced. Chloroform gas causes breathing difficulty and can cause you to pass out so that you can't get to fresh air. Breathing too much chloroform gas for too long can cause death.

    Chloroform has a distinctly different smell than chlorine bleach or alcohol. It smells sweet. Mixing the two chemicals can also produce chloroacetone, dichloroacetone, and hydrochloric acid. These chemicals can cause burns, organ damage, and lead to the formation of cancers.

    Continue to 5 of 7 below.
  • 05 of 07

    Bleach (Sodium hypochlorite) and Acetone

    Mixing chlorine bleach and acetone (fingernail polish remover) produces chloroform gas. While not usually used together, the products are used in the laundry room and bathroom to remove stains and should be stored safely away from each other.

  • 06 of 07

    Vinegar (Dilute acetic acid) and Hydrogen Peroxide

    In an attempt to clean and disinfect surfaces, you may be tempted to mix distilled white vinegar and hydrogen peroxide. You will get a stronger disinfectant for surfaces but you will also create peracetic acid.

    Peracetic acid can cause chemical burns, irritate your eyes and respiratory system, and cause corrosion on some surfaces.

  • 07 of 07

    Flammable Chemicals and Combustion

    Combustion is a physical and chemical reaction that can occur with flammable liquids like solvents, paint strippers, alcohol, fuels, and pressurized gases. The key to avoiding accidents is proper storage.

    Ideally, any flammable liquid should be stored in small amounts in the original safety cans in an Underwriter Laboratory (UL)-approved flammable liquid storage cabinet. The cabinet should be located away from heat sources and any spark-inducing equipment that could ignite vapors.

    If a spill occurs, clean-up must be handled with care to prevent fumes from igniting. Even the heat of a clothes dryer can ignite fabrics that have been exposed to excessive amounts of flammable chemicals.