Test for Anions,
Identification of gases e.g CO2, SO2 and O2.
Characteristics test for anions e.g SO42-,SO32-,CO32-,NO-3, Cl–, etc.
The anions are negatively change ions examples of anions are SO42-,SO32-,CO32-,S2- etc.
Identifications of gases:
| H2 | It gives a ‘pop’ sound when the gas is contact with a lighted splint. |
| O2 | It rekindles a glowing splint. |
| CO2 | It is colourless and odourless. It turns lime water milky. |
| Cl2 | A green wish yellow gas, it turns moist iodide paper black. |
| SO2 | Colourless gas with irritating smell. It turns damp blue litmus paper to red. That is acidic gas. |
EVALUATION
- State two (2) examples of anions with their gases.
- Identify Cl2 and NH3 gases.
GENERAL EVALUATION
- Give the common reagents for confirmatory test of anions
- State how you would confirm/test for NO3-
- Name three gases that are colourless and acidic to litmus.
- Sodium chloride and silver trioxonitrate(V) crystals are separately soluble in water to give colourless solutions. Explain what happens when their solutions are mixed together.
READING ASSIGNMENT
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School Chemstry by O.Y Ababio pages 165 – 183
Practical Chemistry by R. I Makanjuola pages 27-33.
Practical Chemistry for Schools and Colleges by Godwin O. Ojokuku pages 30 – 98.
WEEKEND ASSIGNMENT
- Brown ring test is used to confirm (a) S2- (b)NO3- (c) SO42- (d) SO32-
- The presence of SO32- change the colour of acidified K2Cr2)7 from (a) green to red (b) purple to colourless (c) orange to green (d) green to orange
- A greenish yellow gas that change moist iodide paper black is (a) Cl2 (b) SO2 (c) H2 (d) O2
- Sometimes in the presence of conc HsSO4, copper turning and heat NO3- gives (a) brown ring reaction (b) pure brown fume (c ) reddish brown (d) effervescence
- The gas that turns lime water milky is (a) H2 (b) SO2 (c) NH3 (d) CO2.
THEORY
- State the colour of these solutions a. KMnO4 b. K2Cr2O3 c. HOBr d. CuSO4.5H2O e. Ca(OH)2
- Carry out the following exercises on sample K. add about 10cm3 of distilled water to K in a test tube. Divide the solution into four.
- To the 1st portion add NaOH drop wise and in excess.
- To the 2nd portion add NH3 solution drop wise and then in excess.
- To the 3rd portion, add it drops of BaCl2 follow by the addition of dil HCl
- To the 4th portion, add dil HCl follow by the addition of BaCl2.
Record your observation and inferences then name the salt K.
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