39 Insightful Publications
Aim of this experiment is to study the nature of the oxide formed by burning a magnesium ribbon and perform the dilution of acids and bases.
Magnesium burns with a dazzling white flame in the presence of air to form magnesium oxide.
2Mg (s) + O2 (g) → 2MgO (s)
Magnesium oxide is basic in nature as it dissolves in water to form magnesium hydroxide.
MgO (s) + H2O (l) → Mg(OH)2 (aq)
Hence, the aqueous solution of magnesium oxide turns red litmus blue.
The process of mixing an acid or base with water is called dilution. This results in a decrease in the concentration of ions per unit volume. The process of dilution of an acid or a base is highly exothermic.It is important to note that the acid or base should be added to water, but the converse is not true. We should never add water to the acid or base.
To perform this experiment, apparatus and chemicals are required: Sandpaper, pair of tongs, watch glass, bunsen burner, wash bottle, magnesium ribbon, phenolphthalein, concentrated HCl, naOH pellets, distilled water in a 100 mL beaker
Experiment Procedure
To understand the chemical properties of acids and bases, we have to follow the given procedure.
Burning of Magnesium Ribbon
- Take a magnesium ribbon and clean it with sandpaper.
- Hold the magnesium ribbon with a pair of tongs and burn it in the air with a burner.
- Collect the white powder obtained on the watch glass.
- Transfer the white powder into a beaker containing distilled water and mix them.
- Pour a few drops of phenolphthalein into the solution and record your observations.
Dilution
- Take 2 beakers of capacity 100 mL each, containing distilled water, labelled ‘A’ and ‘B’.
- Add a few drops of concentrated hydrochloric acid to beaker ‘A’.
- Note the temperature of beaker ‘A’.
- Now, add a few pellets of sodium hydroxide to beaker ‘B’.
- Note the temperature of beaker ‘B’.
We can conclude that oxides of metals such as magnesium are basic in nature. Phenolphthalein gives a pink colour in a basic medium. The dilution of an acid or a base with water results in a decrease in the concentration of ions per unit volume. The H+ ions from acids combine with water molecules to form hydronium ions (H3O+).
FAQs on Chemical Properties of Acids and Bases III
Q1. Which gas evolved when magnesium reacts with hydrochloric acid?
Answer: When an acid reacts with a metal, hydrogen gas is evolved and a corresponding salt is formed. For example, when magnesium reacts with hydrochloric acid to form magnesium chloride and hydrogen gas. H2 gas extinguishes the burning splinter with a pop sound.
Mg(s) + 2HCl(l) → MgCl2(aq) + H2(g)
Q2. Explain about the chemical reaction between magnesium and water and the nature of the product?
Answer: The oxides of all metals are basic in nature. Hence, when we dissolve magnesium oxide in water, it forms magnesium hydroxide, which is basic in nature. A basic solution can change the colour of red litmus to blue.
Mg(s) + 2H2O(l) → Mg(OH)2 (aq) + H2 (g)
Q3. Which gas produces a pop sound?
Answer: H2 gas extinguishes the burning splinter with a pop sound. It is produced when acids react with metals.
Q4: What is the product formed on burning a magnesium ribbon?
Answer: A magnesium ribbon burns with a white dazzling flame in the air to form magnesium oxide.
2Mg (s) + O2 (g) → 2MgO (s)
Q5: What indicators are used to detect the nature of Mg(OH)2?
Answer: A magnesium hydroxide solution is basic in nature. So, phenolphthalein will turn a pink, methyl orange will turn yellow and red litmus will change to blue in a Mg(OH)2 solution. Thus, all these indicators can detect the nature of a Mg(OH)2 solution.
JEE Main