test for anions and gases

• chlorine - chlorine bleaches damp litmus paper, turning it white. (it was turn red for a moment because a solution of chlorine is acidic)
• oxygen - if you put a glowing splint inside a test tube containing oxygen, the oxygen will relight the glowing splint
• carbon dioxide - bubbling carbon dioxide through an aqueous solution of calcium hydroxide (limewater) causes the solution to turn cloudy
• hydrogen - if you hold a lit splint at the open end of a test tube, containing hydrogen, you will get a squeaky pop (the noise comes from the hydrogen burning quickly with the oxygen in the air to form H2O)
• test for anions often give precipitates
• you can test whether a mystery solution contain carbonate ions by putting a sample in a test tube then using a dropping pipette to add a couple of drops of dilute acid. connect test tube to a test tube of limewater. If carbonate ions are present, carbon dioxide will be released and turn limewater cloudy when it bubble through it
• to identify sulfate ions, use a dropping pipette to add a couple of drops of dilute hydrochlorid acid followed by a couple drops of barium chlroide solution to the test tube containing mystery solution. If sulfate ions are present, a white precipitate of barium sulfate will form
• to identify a halide ion, add a couple of drops of dilute nitric acid followed by a couple drops of silver nitrate solution to your mystery solution. Chloride gives a white precipitate of silver chloride. Bromide gives a cream precipitate of silver bromide. An iodine gives a yellow precipitate of silver iodine