Test for Anions

Question 1

What does hydrochloric acid help detect

Answer 1

Carbonates

Question 2

How to test for carbonates

Answer 2

• add dilute hydrochloric acid (HCl) to test sample
• if carbonates (CO3^2-) present, the carbon dioxide will be released
• test CO2 with limewater

Question 3

Carbonate + acid —>

Answer 3

Carbon dioxide + water

Question 4

What is used to test for sulfates

Answer 4

With HCl and barium chloride

Question 5

What colour precipitate do sulfate ions produce?

Answer 5

White precipitates

Question 6

Method of testing for sulfates

Answer 6

• add dilute HCl, followed by barium chloride solution, BaCl2
• if a white precipitate of barium sulfate forms, means original compound was a sulfate

Question 7

Why is HCl added to the the possible sulfate compound?

Answer 7

To get rid of traces of carbonate or sulfite ions before the test.
These could both produce a precipitate, and confuse results

Question 8

Barium ions + sulfate ions —>

Answer 8

Barium sulfate (BaSO4)

Question 9

What is used to test for Halides

Answer 9

Silver Nitrate

Question 10

Steps for testing for halides : chloride, bromide, iodide

Answer 10

• add dilute nitric acid (HNO3), followed by silver nitrate solution (AgNO3)

Question 11

What precipitate and colour is it is a chloride ions is present

Answer 11

Silver chloride
White

Question 12

What precipitate and colour is it if a bromide ions is present?

Answer 12

Silver bromide
Cream

Question 13

What precipitate and colour is it if a iodide ion is present

Answer 13

Silver iodide
Yellow