A student added some bromine (reddish orange) in some carbon tertra chloride ro a sample of butane in a test tube and placed it in a dark cupboard. When the student removed the test tube it still had the reddish orange colour. When the test tube was left on the table top it was observed that the reddish orange colour gradually faded and white fumes produced.
with the aid of an equation explain clearly the the observations of the student.
C4H10 + Br2 + no light ==> No reaction.
C4H10 + Br2 + light ==> C4H9Br + HBr
light catalyzes the reaction. The color of the Br2/CCl4 solution faded because the Br2 was used.
First, let's examine the observations of the student:
1. The student added bromine (reddish-orange) to carbon tetrachloride and butane in a test tube.
2. After some time in a dark cupboard, the test tube still had the reddish-orange color.
3. When the test tube was left on the table top, the reddish-orange color gradually faded.
4. White fumes were produced during this fading process.
Based on these observations, it can be inferred that the butane reacted with the bromine. Let's explain the observations in the context of a possible reaction using the following equation:
C4H10 + Br2 -> C4H9Br + HBr
The reaction between butane (C4H10) and bromine (Br2) results in the formation of 1-bromobutane (C4H9Br) and hydrogen bromide (HBr).
Explanation of the observations:
1. Initially, when the student added bromine to carbon tetrachloride and butane, the bromine molecules (Br2) were in the liquid state and had a reddish-orange color. Carbon tetrachloride is a nonpolar solvent that does not react with bromine but helps to dissolve it.
Equation: Br2 (liquid) + CCl4 (carbon tetrachloride) -> Br2 (dissolved in carbon tetrachloride)
2. The test tube was placed in a dark cupboard, which did not provide any additional reactants or conditions for the reaction. Therefore, no significant change occurred, and the bromine color remained in the test tube unchanged.
3. When the test tube was left on the table top, it was exposed to air containing oxygen. Oxygen can initiate a reaction between bromine and butane. The red-orange color gradually faded as the bromine was consumed in the reactions.
4. The fading of the reddish-orange color was accompanied by the production of white fumes. These white fumes suggest that hydrogen bromide gas (HBr) was formed during the reaction and escaped from the test tube. The reaction with butane produced 1-bromobutane and hydrogen bromide gas.
Overall, the observations suggest that the bromination reaction of butane with bromine occurred, resulting in the formation of a new compound (1-bromobutane) and the release of hydrogen bromide gas.