Question 27 of 28intermediate🔧 ApplyShort Answer2 marks

Give a test that can be used to differentiate between saturated and unsaturated hydrocarbons.

Correct Answer

Combustion test can be used to differentiate between saturated and unsaturated hydrocarbons. When burned, saturated hydrocarbons generally give a clean flame, while unsaturated hydrocarbons give a yellow flame with lots of black smoke.

The yellow flame from unsaturated compounds produces a sooty deposit on surfaces. However, it is important to ensure sufficient air supply during the test, as limiting air can cause even saturated hydrocarbons to give a sooty flame due to incomplete combustion.

Exercise: EXERCISES | Q: 14 | (Page 20)
For More Understanding

Explanation

The textbook context clearly states in Activity 4.4 that 'Saturated hydrocarbons will generally give a clean flame while unsaturated carbon compounds will give a yellow flame with lots of black smoke.' This is a standard 2-mark answer that directly addresses the question using only the provided information. The answer also includes the important caveat mentioned in the text about air supply affecting the results.

Solution Steps

  1. Step 1: Burn the hydrocarbon sample in air.

  2. Step 2: Observe the colour and nature of the flame produced.

  3. Step 3: A clean flame indicates saturated hydrocarbon; a yellow sooty flame indicates unsaturated hydrocarbon.

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