Pag 4 - qualitative analysis of ions

Question 1

How do you identify the negativ ion present in unknown mixture

Answer 1

• add 25cm3 of distilled water into a 100cm3 beaker
• add mixture into the water and stir with a glass rod until most of the solid has dissolved
• filter the mixture into a conical flak
• add about 2 cm 3 of the filtrate into a test tube
• add 5 drop of HNO3 followed by 10 drops of AgNO3 to the test tube and record any obervations
• to the same tet tube add NH3 dropwise until there is not further colour change record any overervations
• add 1 spatular of the residue to a test tube add 2cm3 of HNO3 and keep adding till no further reaction record any observations
• use you observations to ugget formula of the two anion in mixture and write equations for for oberved reactions

Question 2

How do you identify the group 2 poitive ion

Answer 2

• add 2cm3 of the filtrate add 2cm3 off ulfuric acid to the test tube and record oberservation
• in a new test tube add 2cm3 of filtrate by 2cm3 of K2Cr2O4 record observation
• deduce from the table

Question 3

What is the table to identify the group 2 positive ion

Answer 3

• magnesium -soluble in sulfate - soluble in chromate
• strontium - insoluble in sulfate - soluble in chromate
• barium - insolbule in sulfate - insoluble in chromate

Question 4

What are the safety measures for qualitative analysis

Answer 4

• mixture - unknown so treat a toxic via all expoure routes
• nitric acid - cause severe skin burns and eye damage
• silver nitrate - causes sever skin burns and eye damge
• ammonia - severe skin burns and eye damage toxic if inhaled
• sulfuric acid - cause severe skin burns and eye damage
• potassium chromate - causes skin irritation and serious eye irritation may cause and allergic skin reaction causes respiratory irritatation may cause cancer and genetic defects