More tests for ions

Question 1

What type of ions/elements are:
sulfur
carbon
iodine
bromine
chlorine

Answer 1

non-metals

they form negative ions

Question 2

test for carbonate ions

Answer 2

1) place the substance in the bottom of a test tube
2) fill another test tube with limewater and connect it to the other test tube using a bung and delivery tube
3) add HCl/an acid to the original test tube
4) if it bubbles and the limewater turns cloudy it is a carbonate (as it is giving off CO2)

Question 3

test for sulfate ions

Answer 3

1) place the substance in the bottom of a test tube
2) add dilute HCl to the test tube
3) add barium chloride (BaCl[2]) solution to the test tube
4) if a white precipitate forms the substance contains a sulfate ion

Question 4

tests for halide ions

Answer 4

1) add the substances to the test tubes
2) add a few drops of nitric acid
3) add silver nitrate solution

4) chloride ions form a white precipitate
bromide ions form a cream precipitate
iodide ions form a yellow precipitate

Question 5

test for ammonium ions

Answer 5

1) add sodium hydroxide solution to the substance in a boiling tube
2) heat the boiling tube
3) use a bung to collect the gas produced
4) if it contains ammonium ions, ammonia gas will be produced, as well as water

Question 6

test for ammonia gas

Answer 6

• damp red litmus paper turns blue
• hydrogen chloride gas (from concentrated hydrochloric acid) reacts with ammonia to form a white smoke of ammonium chloride

ammonia has a characteristic sharp smell

Question 7

equations for ammonium ions test and ammonia gas test using hydrogen chloride gas

Answer 7

NH[4][+] + OH[-] -> H[2]O + NH[3]
(aq) (aq) (l) (g)

NH[3] + HCl -> NH[4]Cl
(g) (g) (s)