Neutralisation 101

In Science, we have been learning about the topic Acids and Bases. When an acid and a base get mixed together, a chemical reaction can occur. A base cancels out the effects of the acid, and when this happens it is called a neutralisation as when you add just  the right amount of acid and base together, you get a neutral solution.


Aim: To observe a neutralisation reaction
Equipment:

• A test tube
• Test tube rack
• 1 mol L-1 Na2CO3 (Sodium carbonate)
• 1 mol L-1 HCI (Hydrochloric acid)
• Dropper or Dropper Bottle 
• Universal Indicator Solution 

Method:

1. Place approximately 1-2ml  of sodium carbonate to a test tube and place the test tube in the test tube rack. Then, add 3-5 drops of the Universal Indicator solution. 
2. Using the dropper bottle, add HCI drop by drop, slowly. You need to be very careful with how much you add in as even a little bit extra, you may miss the neutralisation point. 

Observations/Results

It's very hard to get it to neutral especially when you add just the smallest bit over. Getting the colour to a nice green colour took us a while, with it going between to colours the most; red and indigo. But after a while, we managed, as a group to get it to green. Well, Jess, Nadia and Molly did. The closest that I got to a green colour was a very off yellowish green. After we played around a bit, had a competition to see who could get it to green the fastest and actually got it to green, we got told we could make a rainbow. A good rainbow. Which we managed to do. Not with all of the fourteen colours but with five, which covered the length of the pH scale. The colours that we made into a rainbow were red, then to orange and yellow.Green, Blue and a purple-ly indigo colour to finish. 

Red is the strongest acidity of all the acids and then indigo is the strongest base. Red, orange and yellow are all acid, while the blues and indigo's are all bases. The green, as you may have realised by now, is the neutral colour, at pH seven. This was a very interesting experiment as you got completely different results from another team. It may have been easier for another team to get to the pH seven, or the may not have been able to get it green at all. 

Just to the side is the rainbow that we made. It also features the tips of someones finger? Okay. As it turns out, it's my finger. :)

Overall, this was a very exciting experiment and I can't wait until we get another chance to do an experiment like this.