Question

Propane is one of the major components of liquefied petroleum gas (LPG). The petroleum industry uses a process to produce another alkane and two alkenes from propane according to the equation below.
2CH3CH2CH3 (g) ------> X (g) + Y (g) + CH2 ═ CH2(g) + H2 (g)
A. (i) Identify the process represented by the equation.
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(ii) State the conditions at A.
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(iii) Write the condensed structural formulae of
X ...........................................................................................................................
Y ........................................................................................................................... [2 marks]

B. (i) Account for the tetravalency of the carbon atom.
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(ii) Aqueous bromine will only react with propane in sunlight but aqueous bromine reacts quickly with propene without sunlight.
Using appropriate notation and equations, explain the steps involved in the mechanism of the chemical reaction of aqueous bromine with propane (in sunlight) and aqueous bromine with propene (without sunlight). [8 marks]


(iii) Name the mechanism of the reaction selected in (b) (ii).
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C. Describe the observations expected when
(i) aqueous bromine is added to liquid heptane (in sunlight)
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(ii) acidified potassium permanganate solution is added to liquid heptene (without
sunlight.)
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................................................................................................................................. [2 marks]

Answer 1

PubChem CID6334Structure

Chemical

Molecular FormulaCH3CH2CH3 or C3H8Synonyms

PROPANE

n-Propane

Dimethylmethane

propan

Propyl hydride

Molecular Weight

44.1 g/mol

Description

Propane appears as a colorless gas with a faint petroleum-like odor. It is shipped as a liquefied gas under its vapor pressure. For transportation it may be stenched. Contact with the unconfined liquid can cause frostbite by evaporative cooling. Easily ignited. The vapors are heavier than air and a flame can flash back to the source of leak very easily. The leak may be either a liquid or vapor leak. The vapors can asphyxiate by the displacement of air. Under prolonged exposure to fire or heat the containers may rupture violently and rocket.

HOPE YOU UNDERSTOOD

Answer 2

Answer:

Xylom:-

• It conducts water and minerals.

• Conduction is mostly unidirectional i.e. from roots to apical parts of the plant