tests for ions

Question 1

testing for carbonates

Answer 1

• add dilute acid to your sample and if a carbonate is present carbon dioxide will be released.
• bubbling/ effervesces

Question 2

testing for sulfates

Answer 2

• add dilute hcl followed barium chloride solution
• white ppt (barium sulphate) forms which is insoluble in water.

Question 3

testing for carbon dioxide

Answer 3

• bubble gas through limewater > turns cloudy if carbon dioxide present

Question 4

test for halides

Answer 4

react w silver nitrate
br- cream ppt
I - yellow ppt
cl - white ppt

using ammonia to detect halide solubility
br - dissolves in dil only
cl - dissolves in conc, dil
I - insoluble in dil, conc

Question 5

testing for ammonium gas/ ions

Answer 5

• ammonium gas is alkaline so test using red litmus paper ( turns blue).
• ammonium ions - add sodium hydroxide and heat if ammonia given off there’s ammonium ions

Question 6

what false positives do u need to be aware of when testing for sulphates

Answer 6

barium carbonate and sulphite are also insoluble as well as baranium sulphate when using baranium chloride

Question 7

what false positives do u ned to be aware of when testing for halide ions

Answer 7

sulfate ions also react with silver nitrate to form a ppt

Question 8

what is a way to ensure there are no false positives when testing for sulphates and halide ions

Answer 8

add dilute acid - neutralise any unwanted anions.

Question 9

How do I produce Ammonia gas

Answer 9

React carbonate with a warm sodium hydroxide solution

Question 10

ammonium carbonate formula

Answer 10

(NH4)2CO3