Qualitative analysis

Aq. NaOH is added to a sample of solution L. The mixture is warmed. A gas is produced. The gas turns damp red litmus paper blue. What is the gas produced?

• Oxygen gas

• Carbon dioxide gas

• Chlorine gas

• Ammonia gas

Solution M is added to dilute hydrochloric acid. Effervescence is seen. A gas is produced. The gas turns limewater milky. Name the anion in solution M.

• Cl^-

• NO^-₃

• CO^2-₃

• SO^2-₄

Dilute HNO₃ and aq. Ba(NO₃)₂ are added to solution N in a test tube. A white precipitate is formed. Name the ion present in N.

• SO^2-₄

• Ca²⁺

• Cl^-

• Zn²⁺

Choose the test for water vapor.

• Red litmus paper turns blue

• Blue cobalt chloride paper turns pink

• Blue litmus paper turns red

• Universal indicator changes to violet.

Solid K reacts with dilute hydrochloric acid to form a solution. Choose a test to show that this solution contains Ca²⁺ ions.

• Aq. NH³ - no ppt forms

• Aq. NaOH - white ppt, soluble in excess

• Aq. NH³ - white ppt, insoluble in execss

• Aq. NaOH - green ppt, insoluble in excess

A is a colorless solution of an oxidizing agent. What would you see if you add A to aq. KI until no further change occurs?

• Orange to green

• Green to orange

• Brown to colorless

• Colourless to brown

Name the separation technique if you need to separate colored dyes.

• Distillation

• Evaporation

• Chromatography

• Filtration

Ethanol has a lower boiling point than pure water. How would you separate a mixture of ethanol and water?

• Crystallisation

• Evaporation

• Boiling

• Simple distillation

PbCl₂ is an insoluble salt. Name the preparation method for PbCl₂ and state the reagents to make PbCl₂.

• Precipitation method - Pb and Cl₂

• Titration method - Pb(OH)₂ and HCl

• Precipitation method - Pb(NO₃)₂ and NaCl

• Titration method - PbO and NaCl

Name the apparatus used to measure fixed volume of liquid.