A-Level CIE Chemistry 4.2 Organic & Inorganic Chemistry Practicals: Qualitative Analysis

At each st

Question

Qualitative Analysis

At each stage of any test you are to record details of the following.
- colour changes seen
- the formation of any precipitate
- the solubility of such precipitates in an excess of the reagent added

When gases are released they should be identified by a test, described in the appropriate place in your observations.
Marks are not given for chemical equations.
No additional tests for ions should be attempted.

If any solution is warmed, a boiling tube MUST be used.

Rinse and re-use test-tubes and boiling tubes where possible.

Where reagents are selected for use in a test, the full name or correct formula of the reagents must be given.

(a)
FA 7 contains one cation and one anion from those listed in the Qualitative Analysis Notes on pages 10 and 11.

Put two spatula measures of FA 7 into a test-tube.
Add about two drops of a test-tube of dilute hydrochloric acid to your solution of FA 7.

(i)
Add 5 drops of aqueous silver nitrate to your solution of FA 7.

(ii)
Put a very small spatula measure of solid FA 7 into a hard glass test-tube.
Hold the test-tube horizontally and heat it gently for a few seconds, then heat it strongly until no further change takes place.
Leave the test-tube to cool to room temperature.
While cooling takes place, move on to (iv).
In the space below record the observations made at each stage in an appropriate form.
State your conclusion.

(iii)
State what deductions you can make about the identity of the anion in FA 7 from the tests above.

(iv)
Use the information in the Qualitative Analysis Notes on pages 10 and 11 to select a further test to confirm the identity of the anion in FA 7.

test

Carry out this test and, in the space below, record the observation(s) made in an appropriate form. State your conclusion.

(v)
The cation in FA 7 is aluminium ion, calcium ion or zinc ion.
Select one reagent to identify the cation in FA 7.

reagent

Use this reagent to carry out a test.
Record the observation(s) made and identify the cation.

(b)
FA 8 contains one cation from those listed on page 10 and 11.

Put all of the FA 8 into a test-tube.
Add about 10 cm³ of distilled water and dissolve the solid.
Allow the mixture to stand for two minutes.

Use a dropping pipette to transfer about 1 cm³ of the mixture from the top of the test-tube to another test-tube. Add 5 drops of starch solution.
Record all of your observations.

(ii)
State what type of chemical behaviour has been shown by potassium iodide in this reaction. Give an ionic equation to justify your answer.

(iii)
To another 1 cm depth of solution of FA 8 in a test-tube, add aqueous sodium hydroxide.
Record the observation(s) made.
Give the ionic equation for the reaction taking place.

Qualitative Analysis At each stage of any test you are to record details of the following - CIE - A-Level Chemistry - Question 3 - 2011 - Paper 1

Worked Solution & Example Answer:Qualitative Analysis At each stage of any test you are to record details of the following - CIE - A-Level Chemistry - Question 3 - 2011 - Paper 1

Put two spatula measures of FA 7 into a test-tube.

Add about two drops of a test-tube of dilute hydrochloric acid to your solution of FA 7.

Add 5 drops of aqueous silver nitrate to your solution of FA 7.

Put a very small spatula measure of solid FA 7 into a hard glass test-tube.

While cooling takes place, move on to (iv).

State what deductions you can make about the identity of the anion in FA 7 from the tests above.

Use the information in the Qualitative Analysis Notes on pages 10 and 11 to select a further test to confirm the identity of the anion in FA 7.

Select one reagent to identify the cation in FA 7.

Record the observation(s) made and identify the cation.

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