How to Dissolve Magnesium Oxide in Concentrated HCL

Written by damien thryn
  • Share
  • Tweet
  • Share
  • Pin
  • Email
How to Dissolve Magnesium Oxide in Concentrated HCL
Extreme care must be taken when working with Hydrochloric acid. (chemical experience image by Sergey Galushko from

The dissolution of magnesium oxide (MgO) in concentrated hydrochloric acid (HCl) is an exothermic reaction that results in the production of magnesium chloride (MgCl(2)) and water. According to the chemistry separtment at Southeast Missouri State University .35 grams of MgO mixed with 50ml concentrated HCl will result in the complete dissolution of the MgO into the HCl solution. The chemistry department at the University of Houston points out that safety precautions must be taken when working with concentrated HCl due to its volatile nature. Clark University recommends that special laboratory hoods be worn while working with HCl and that hazardous waste containers be used to dispose of any unwanted reactants or products. Dissolving magnesium oxide into hydrochloric acid is a delicate process but one that is common in university chemistry courses.

Skill level:

Things you need

  • Laboratory safety hood
  • Lab gloves
  • 50ml concentrated hydrochloric acid (HCl)
  • Plastic mixing container
  • .35 grams magnesium oxide (MgO)
  • Stirring stick
  • Hazardous waste disposal container

Show MoreHide


  1. 1

    Don protective gear, including a laboratory hood and lab gloves capable of protecting skin from injury if the concentrated HCl splashes outside of a container. HCl in any form is a dangerous substance that can cause serious chemical burns if it comes into contact with flesh.

  2. 2

    Pour the 50ml sample of HCl into the plastic mixing container. It is vital to use extreme care when transferring the liquid HCl from one container to another. Pour slowly and carefully to avoid splashing the acid outside its container. A plastic mixing container is necessary because metal and many other materials can dissolve in HCl

  3. 3

    Place the .35 gram sample of MgO into the plastic mixing container with the HCl. It is important not to dump the MgO into the HCl too quickly or in a manner that splashes the HCl outside of the plastic mixing container.

  4. 4

    Stir the contents of the mixing container with the stirring stick. The reaction may take up to 20 minutes to finish, and you should stir the reactants slowly to ensure the reaction is as complete as possible.

    How to Dissolve Magnesium Oxide in Concentrated HCL
    Water is one of the substances that will result from mixing HCl and MgO. (water drop and water rings image by glgec from
  5. 5

    Dispose of the reaction byproducts in an appropriate hazardous waste container. You can separate the resulting mixture of liquid water and liquid magnesium chloride and refine into other useful elements.

Tips and warnings

  • Consider using an eye dropper or other plastic based controlled liquid dispensing mechanism in order to more carefully and accurately move the HCl into the mixing container.
  • The resulting magnesium chloride reaction product can be further refined and utilised in a number of industrial applications. The dissolution of MgO into HCl is a common method of refining magnesium chloride.
  • Use extreme caution when handling hydrochloric acid, especially in a concentrated form. It is a highly volatile substance that can react with water in cellular tissue and cause serious burns.

Don't Miss

  • All types
  • Articles
  • Slideshows
  • Videos
  • Most relevant
  • Most popular
  • Most recent

No articles available

No slideshows available

No videos available

By using the site, you consent to the use of cookies. For more information, please see our Cookie policy.