JPJC 2026 Alkane Assignment

2026 JPJC J1 H2 Chemistry (9476) 1 [Turn Over JURONG PIONEER JUNIOR COLLEGE 2026 JC1 H2 Chemistry (9476) Topical Assignment Topic 9: Alkanes Name : __________________________________________ 18 Class : 26S ___ Date : ____________ Bond Linkage −1 / NA Duration : 30 minutes 1 2-bromopropane, CH 3CHBrCH3, reacts with chlorine to form a mono -chlorinated compound which exhibits stereoisomerism. (i) Write a balanced equation for the reaction. __________________________________________________________ [1] (ii) State the conditions required for this reaction and the type of reaction undergone. Conditions: _____________________________ Type of reaction: _____________________________ [2] (iii) Describe the mechanism for the above reaction. [3]

2026 JPJC J1 H2 Chemistry (9476) 2 (iv) State the type of stereoisomerism the product exhibited and draw appropriate diagrams to illustrate the stereoisomers. Type of stereoisomerism: ________________________ [3] (v) Explain why the reaction does not require prolonged radiation of ultraviolet light. _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ [1] 2 An alkane A, C 4H10, when reacted with bromine, forms only two isomeric monobromo compounds, B and C, with the formula C4H9Br. Compound B exhibits stereoisomerism but not compound C. (i) Draw the structure of A, B and C. [3] (ii) Suggest, with a reason, the approximate ratio in which B and C were formed. _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ [2] [Total: 15]

2026 JPJC J1 H2 Chemistry (9476) 3 [Turn Over 3 Which of the following represents a valid propagation step in the reaction between ethane and chlorine? Which statements about the process are correct? A CH3CH3 + Cl• ⟶ CH3CH2Cl + H• B •CH2CH3 + Cl• ⟶ CH3CH2Cl C CH3CH2Cl + Cl• ⟶ •CH2CH2Cl + HCl D CH3CH2Cl + H• ⟶ CH3CH2• + HCl 4 The molecule, Q, with molecular formula C6H14 has the following structural formula Q CH3CH2CH(CH3)CH2CH3 Q reacts with chlorine to form monochloro compounds C6H13Cl. How many possible constitutional isomers, each with formula C6H13Cl, could be formed by Q? A 3 B 4 C 5 D 6 5 Propane undergoes free -radical substitution when mixed with chlorine and exposed to ultra -violet light. Which compounds are possible products from this reaction? 1 CH3CH2CH2Cl 2 CH2ClCH2CH2Cl 3 CH3CH2CH2CH2CH2CH3 4 CH3CH2CH2CH2CH3 A 1, 2, 3 and 4 B 1, 2 and 3 C 1 and 4 only D 2 and 3 only