acids & alkalis

• To test how alkaline or acidic a substance is we can use pH paper or universal indicator
• the more we dilute an acid the more the pH increases/goes up the scale
• the more we dilute an alkali the more it goes down the pH scale
• if an alkali will be added to an acid the pH will go up to 7
• if an acid will be added to an alkali the pH will go up to 7
• neutralisation is when an acid and base react to form water and a salt
• electrolysis and flame tests can be used to identify the elements in a salt
• 1 - red
• 2 - 3 -> red/orange
• 4 - 6 -> yellow
• 7 -> neutral (green)
• 8-9 -> green/blue
• 10-12 -> dark blue/purple
• 13-14 -> purple
• tomatoe juice - pH4
• vinegar -pH3
• bleach- pH12-14
• hand soap - pH10
• water -pH7 neutral
• red cabbage gods a different colour in acid , alkali and neutral solutions so it could be used as an indicator