Demonstrating that sulphuric is dibasic: Aim: The aim of my plan is to demonstrate that sulphuric acid is dibasic. Introduction: Acid is a substance that reacts with a base to form a salt and water similarly a base is a substance that reacts with an acid to form a salt and water. “Lewis (a scientist) states that an acid is a compound that accepts a pair of electrons from a base and a base is a molecule or an ion that donates a pair of electrons to an acid. Acids taste sour and are corrosive and bases are slippery”. ? Acid + Base i?? Salt + Water Acid + Metal i?? Metal Salt + Hydrogen gas
Prediction: I predict that sulphuric acid, H2SO4 is dibasic because it forms two hydrogen (H+) ions in an aqueous solution. It is the molecule of sulphuric acid which changes to sulphate ions (SO42-) and hydrogen ions (H+) when dissolved in water. However, hydrochloric acid is monobasic as it only forms one hydrogen (H+) ion in an aqueous solution. To prove this, I am going to carry out two different experiments that involve a titration and collection of a gas. I assume that it should require me half a volume of sulphuric acid to neutralise sodium hydroxide, NaOH than HCl in titration.
In the collection of gas, I expect to collect double the volume of gas when metal reacts with H2SO4 than that of produced in the reaction with HCl. To prevent irritant substances from coming in contact with my skin Method: Titration: 1. Pour in 100cm3of sulphuric acid and 100cm3of Sodium hydroxide in two separate beakers and label them with their corresponding names, H2SO4 and NaOH. 2. Rinse burette first with distilled water then with small amount of H2SO4 while tap is still closed. Leave some of the acid and run it through the tap. 3. Close the tap and clamp the burette.
Make sure it is secure. 4. Using filter funnel, fill burette with H2SO4. 5. Also, rinse conical flask with distilled water first and then with NaOH. 6. Bind pipette filler with pipette and fill in 25 cm3 of NaOH and read lower meniscus. 7. Hold pipette above conical flask and remove the pipette filler which will allow NaOH to run down into it. 8. Put a whit tile underneath burette. 9. Add few drops of phenolphthalein in the conical flask containing NaOH and place it on the tile. 10. Open the tap fully and allow the acid to flow and at the same time swirl the conical flask.
11. If the colour of solution is going lighter, twist the tap so that only drops of acid flow into the conical flask. 12. Keep adding the drops until one last drop changes the colour of the solution to colourless. 13. Close the tap with that last drop and record the reading of the acid that was used in a table. 14. Repeat the same procedure 3 more times and find the average volume of acid used. 15. Carry out exactly the same procedure from step 1 to 13 but using HCl instead of H2SO4. 16. See the figure below for how to set up the apparatus.