Who's Cheating on the Vinegar?

            Vinegar is a weak acid and will react with an alkali - this is a neutralisation reaction. In this investigation I will be given an alkali called sodium hydroxide. If hydroxide is added to vinegar slowly, or visa versa, I will eventually get a neutral liquid.
             Problem.
             Do you like vinegar on your bag of fish and chips? Lots of people do, and many chip shops let you help yourself to the vinegar. But are the manufacturers who supply the shops cheating on them? The manufacturers could be adding water, so the chip shops actually get less concentrated vinegar.
             In this investigation I will get four samples of vinegar (A, B, C and D) from different shops supplied by different manufactures. My job is to carry out a series of tests to see which of the samples from the manufacturer is:-.
             a) The most concentrated,.
             b) The best value for money.
             Prediction/Hypothesis.
            
             • I predict the stronger the vinegar the less watered down it is.
            
             • I expect the experiments to be quite accurate because I am using measurement tools to measure cm3 of liquid.
            
             • I think that all the vinegar is slightly diluted.
            
             • I think the strongest vinegar is the one that takes the most amount of alkali to neutralise.
             Scientific Knowledge.
             An acid is any compound which when dissolved in water will produce Hydrogen cat ions H+. Acids are proton donors. Some common acids are Hydrochloric Acid, Sulphuric Acid and Nitric Acid. The pH of an acid is from 1-6. 1, 2 and 3 are strong acids. 4,5 and 6 are weak acids. They will turn litmus paper red. They are corrosive and have a bitter taste.
             When an acid is reacted with an alkali the alkali and acid neutralise each other and produce a salt + water.
             Apparatus.
             Retort Stand.
             .
             Burette .
             Pipette .
             Pi-pump.
             Sodium Hydroxide.
             .
             4 Conical Flasks .
             4 Vinegar samples x2 .
             Phenol phthalein.
             5 Beakers .
             Funnel .
             Clamp .
             Safety Goggles.
             Plan.
              Independent Variable - We are going to investigate the amount of sodium hydroxide needed to neutralise four different samples of vinegar.