Reactions of Acids with Carbonates Hydrogen Carbonates and Bases

Reactions of Acids with Carbonates, Hydrogen Carbonates, and Bases

Aim / Objective:
To investigate the reactions of Acids with Carbonates, Hydrogen Carbonates, and Bases

Introduction:
Acids are groups of compounds that have at least one hydrogen atom as a part of its molecules. This hydrogen atom plays a major role in its reactions. The strength of an acid is given by its pH value.
When an acid reacts with a carbonate, a salt is produced with the evolution of carbon dioxide.
This gas can be tested for by bubbling the gas through lime-water (dilute solution of calcium hydroxide). If a white precipitate (turns milky) is produced the CO2 is present. The salt made is dependent on the acid and the carbonate that is used.
Bases react with acids to produce a salt and water only. No gas is produced in the reaction so be sure to look for the bases dissolving in the acid.
See Acids, Bases and Indicators under additional information for more details about Acids and Bases.

Materials/Apparatus:
Sodium Hydrogen Carbonate (NaHCO3) Copper (II) Oxide (CuO) Sodium Carbonate (Na2CO3) / marble chips, dilute Sulphuric acid (H2S04), Lime Water Ca(OH)2, dilute Nitric Acid (HNO3) dilute Hydrochloric Acid(HCl), 3 test tubes, test tube rack, spatula,

Method / Procedure:
Place the three test tubes in a test tube rack and label 1, 2, and 3.
To test tube 1, half fill with HCL and add a spatula full of NaCO3
Test with lime water and record results
Half full test tube 2 with HNO3 and add a spatula full of NaCO3. Test with lime water and record results.
To test tube 3, half full with H2SO4 and add a spatula full of CuO. Then gently shake mixture, leave to settle then record results.
Tabulate the results.

Suggested Results:

Table showing reactions of acid with carbonates, hydrogen carbonates and bases

Table showing reactions of acid with carbonates, hydrogen carbonates and bases

Discussion:

1. Write the molecular and ionic equations for each reaction.

Reaction 1:

2 HCL (aq) + Na2CO3(s)        =           2NaCl (aq) + CO2 (g) + H2O (l)

2H+ (aq) + CO2-3(aq)                    =         CO2 (g) + H2O (l)

 

Reaction 2:

2HNO3 (aq) + NaHCO3(s)              =      2NaNO3 (aq) + CO2 (g) + H2O (l)

H+ (aq)     +      HCO3-(aq)                        =      CO2(g) + H2O(l)

 

Reaction 3:

H2SO4 (aq)    +    CuO(s)               =       CuSO4 (aq) + H2O (l)

2H+ (aq)   +    O2-(aq)                        =           H2O (l)

 

2.Write the equation to explain the reactions that occurs when excess carbon dioxide is passed through lime water.

  1. Ca(OH)2(l)   +    CO2(g)                    =                CaCO3(s) + H2O(l)
  2. CaCO3(s)   +   H2O(l)    +     CO2(g)                =        Ca(HCO3)2(aq)

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