Magnesium reaction with hydrochloric acid

The earliest syntheses of boron hydrides were grossly inefficient, giving mixtures of products of A-5% total yields. These procedures were based upon the reaction of magnesium boride with hydrochloric acid. Only much later were yields of 11% obtained when 8N phosphoric acid was used (2). 

FIGURE 17.17 The production of magnesium hydroxide starts with the addition of lime (CaO) to seawater. Reaction of the magnesium hydroxide with hydrochloric acid produces magnesium chloride, which, after drying, is electrolyzed to give magnesium. 

In any chemical reaction, the rate of the reaction can be varied by changing the reaction conditions, such as the concentration of reactants, the temperature, or even the surface area of any solid reactants. In this project, we will address the questions presented to us by the client by reacting magnesium metal with hydrochloric acid under several different sets of reaction conditions and then determine the rate of the reaction by measuring the production of hydrogen gas vs. time. 

FIGURE4.13 Reaction of magnesium metal with hydrochloric acid. The metal is readily oxidized by the acid, producing hydrogen... 

Figure 4.15 Reactions of (a) iron (Fe), p) zinc (Zn), and (c) magnesium (Mg) with hydrochloric acid to form hydrogen gas and the metai chiorides (FeC/2, ZnC/2, MgCi. The reactivity of these metals is reflected in the rate of hydrogen gas evolution, which is slowest for the least reactive metai, Fe, and fastest for the most reactive metal. Mg.

Magnesium reacts with hydrochloric acid to produce magnesium chloride and hydrogen gas. The reactants in this reaction are... 

The more-active metals react with certain acidic solutions, such as hydrochloric acid and dilute sulfuric acid, replacing the hydrogen in the acid. The reaction products are a metal compound (a salt) and hydrogen gas. For example, when soUd magnesium reacts with hydrochloric acid, as shown in Figure 2.5, the reaction products are hydrogen gas and aqueous magnesium chloride. 

Write a balanced chemical equation for (a) the reaction between sodium hydride and water (b) the formation of synthesis gas (c) the hydrogenation of ethene, H,C= GH2, and give the oxidation number of the carbon atoms in the reactant and product (d) the reaction of magnesium with hydrochloric acid. 

A chemical equation shows that as a chemical reaction takes place, reactants are changed into products. The reaction rate of a chemical reaction is often expressed as the change in concentration of a reactant or a product in a unit amount of time. In this activity, the reaction rate will be calculated from the amount of time it takes for a given amount of magnesium (Mg) to react completely with hydrochloric acid (HCI). 

Consider the reaction of magnesium with hydrochloric acid. 

Pour 3-4 ml of a magnesium chloride solution into a test tube and add an ammonia solution. What happens Add a saturated ammonium chloride solution dropwise until the precipitate dissolves. How can the dissolution of the precipitate be explained Introduce into the test tube 1 ml of a sodium phosphate solution. What do you observe Examine the shape of the crystals under a microscope. What is the composition of the crystals Explain the processes that occur. Write the equations of the reactions. Pour hydrochloric acid into the test tube with the crystals. Explain the dissolving of the precipitate. 

Bassam Z. Shakhashiri, "Reactions of Metals and Hydrochloric Acid," Chemical Demonstrations, A Handbook for Teachers of Chemistry, Vol. 1 (The University of Wisconsin Press, Madison, 1983) pp. 25-26. Reactions of iron, zinc, and magnesium with hydrochloric acid produce aqueous solutions of the +2-metal ions and hydrogen gas. 

A major chemical plant dissolved inorganic slurry solids in a series of three fiberglass vessels. Most employees considered this section of the plant as one of the nonhazardous areas of this chemical complex. This area handled a relatively cool sodium chloride (table salt) water stream that was saturated with insoluble salts such as calcium carbonate and magnesium carbonate. The slurry contained about 30-percent calcium carbonate. Insoluble carbonates are treated with hydrochloric acid in two agitated vessels to allow a reaction to liberate carbon dioxide and form a soluble salt. The reaction is a simple one ... 

A solution of pentachlorophenylmagnesium chloride" is prepared from hexachlorobenzene (66 g, 0.23 mol) and magnesium (8.44 g, 0.35 mol) in a mixture of THF (150 ml) and benzene (150 ml) (HAZARD toluene would be preferable). The solution is heated to reflux, and ethyl formate (40 ml, excess) is added by syringe at such a rate that the exothermic reaction maintains refluxing. The mixture is stirred as it is allowed to cool to room temperature during 1 h. Methanol (20 ml) is added, and the solvents are evaporated. The resulting dark-brown residue is washed with hydrochloric acid, methanol and ethyl acetate, and then recrystallized from 4 1 toluene-pyridine, to give bis(pentachlorophenyl)methanol (35 g, 29%). 

Formaldehyde-chromotropic acid test Formic acid, H.COOH, is reduced to formaldehyde H.CHO by magnesium and hydrochloric acid. The formaldehyde is identified by its reaction with chromotropic acid (see Section III.24, reaction 9d) in strong sulphuric acid when a violet-pink colouration appears. Other aliphatic aldehydes do not give the violet colouration. 

The best experimental conditions for the reaction have been discussed. An optimum temperature of 90-105° is easily maintained by the use of a refluxing mixture of benzene and toluene as solvent. Granulated zinc which has been washed with hydrochloric acid can be substituted for the sandpaper-cleaned zinc foil that is sometimes recommended. Magnesium has been used successfully for several condensa tions. ... 

The appearance of a rock indicates that it is a mixture of magnesite (magnesium carbonate, MgCO ), and quartz (SiOo). It is found that 1.00 g of the rock yields 0.430 g of carbon dioxide, on treatment with hydrochloric acid. Write the equation for the reaction, and calculate the percentage of magnesite and the pert entage of quartz in the rock. 

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