急!寫acids, alkalis and neutral solutions的論文. 20分!

Acids have a sour taste. They conducts electricity.They have a pH value lower than 7. They can react with metals that are more reactive than hydrogen to form salt and hydrogen gas. They can react with carbonates and hydrogencarbonates to form salt, carbon dioxide and water. They can react with oxides or hydroxide (base) to form salt and water. Daily examples of acid include citric acid in citrus fruits, ethanoic acid (CH3COOH) in ketchup and vinegar, carbonic acid (H2CO3) in soft drinks, etc.
Alkalis have a bitter taste. They conduct electricity. They have a pH value higher than 7. They can react with acids to from salt and water. They can react with ammonium compounds to produce salt, ammonia gas and water. They can react with most metal ions in aqueous solutions to from insoluble metal hydroxides. Daily examples include sodium hydroxide, calcium hydroxide, ammonia solution, etc.
Neutral solutions have a pH value equal to 7. Daily examples include pure water, sodium chloride solution, etc.
We can test for them with litmus solution. Acids can turn litmus solution red. Alkalis can turn litmus solution blue. Neutral solutions can turn litmus solution purple.

2008-05-12 13:10:48 補充：
Litmus SOLUTION can be used to test for colourless solutions only. It cannot be used to test for coloured solution because the colour will mix together to give an inaccurate result. In this case, you should use a pH meter to test for the pH value of the solutions.

Acid can be divided into two group, inorganic acid (mineral acid) and organic acid. They show acid propreties once they are dissolved into water, as positive hydrogen ions form. Most of the acid properties comes from it. Acids are acidic and give a sour taste and also corrosive. They have pH value lower than 7 and they are only conduct electricity when in molten or aqueous state. They tirms blue litmus paper orange and pH paper red. Once they added into universal indicator, it turns from red to yellow. For phenolphthlein, turms colourless. For methyl orange, turns red. Common examples in daily is carbonic acid in soft drink, ethanoic acid in vinegar, tannic acid in tea, benzoic in soya sause, citric acid in fruit.
For alkalis, they are all soluble base. They have a bitter taste and a feel of slippery and corrosive as it react with the protein and fats in our body. The pH value of it is higher than 7. Like acids, alkalis only show properties and conduct electricity at molten or aqueous state. It turns red litmus paper and pH paper blue and dark blue representatively. Turns phenolphthlein pink or red. Turns unversal indicator green, blue or purple.Turns methyl orange yellow. Common examples are ammonia in glass cleaner, magnessium hydroxide in anti-acids, sodium hydroxide in oven cleaner, slake lime in neutralising acidic soil.
There are several examples of neutral solution. Water and sodium chloride which is commonly called table salt is an example. They have the pH equal 7 and turns universal indicator green. However, it won't change the colour of ph and litmus paper.
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