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FB 5 contains one cation and one anion from those listed in the Qualitative Analysis Notes - CIE - A-Level Chemistry - Question 3 - 2019 - Paper 1
Question 3
FB 5 contains one cation and one anion from those listed in the Qualitative Analysis Notes. (i) Transfer a small spatula measure of FB 5 into a hard-glass test-tube... show full transcript
Worked Solution & Example Answer:FB 5 contains one cation and one anion from those listed in the Qualitative Analysis Notes - CIE - A-Level Chemistry - Question 3 - 2019 - Paper 1
Step 1
Transfer a small spatula measure of FB 5 into a hard-glass test-tube. Heat gently at first and then heat strongly, until no further change occurs.
Answer
Upon heating FB 5, the first observation is the condensation produced on the inner surface of the test-tube, which may appear as droplets. The initial state may show solid form, and as heating continues, the solid substance may start to dissolve, resulting in a gas formation leading to a distinct odor. If there is discoloration or a change to a gas, it would signify a reaction effectively.
Step 2
To a 1 cm depth of dilute hydrochloric acid in a test-tube, add a small spatula measure of FB 5.
Answer
When FB 5 is added to dilute hydrochloric acid, there will likely be fizzing or bubbling observed, indicating a reaction between the acid and the compound. The solution may also change color, depending on the constituents of FB 5, and may result in precipitate formation that alters the visual characteristics of the mixture.
Step 3
Define the formula of FB 5.
Answer
The formula of FB 5 is composed of its respective cation and anion sourced from the qualitative analysis notes. Depending on the ions present, it can be represented in the generic form of a binary compound or perpetual reactant as: , which indicates the combination of ammonium ions and carbonate ions.