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#	Question	Subject and topic	Difficulty
2121	Which reaction converts bromoethane into iodoethane?	Chemistry Preparation and physical properties	Easy
2122	Arrange CH₃Cl, CH₃Br and CH₃I in order of increasing boiling point.	Chemistry Preparation and physical properties	Medium
2123	Which isomer of C₄H₉Br has the lowest boiling point?	Chemistry Preparation and physical properties	Medium
2124	Propene reacts with HBr in the presence of benzoyl peroxide. What is the major product?	Chemistry Preparation and physical properties	Hard
2125	Which haloalkane reacts fastest by the SN2 mechanism?	Chemistry Chemical reactions	Easy
2126	What is the major product when 2-bromobutane is heated with alcoholic KOH?	Chemistry Chemical reactions	Easy
2127	Which product is mainly formed when an alkyl bromide reacts with AgCN?	Chemistry Chemical reactions	Medium
2128	The rate of hydrolysis of (CH₃)₃CBr in aqueous solution does not change when the hydroxide ion concentration …	Chemistry Chemical reactions	Medium
2129	Why is chlorobenzene much less reactive than chloroethane towards nucleophilic substitution?	Chemistry Chemical reactions	Hard
2130	Which molecule contains a chiral carbon atom?	Chemistry Stereochemistry	Easy
2131	Why is a racemic mixture optically inactive?	Chemistry Stereochemistry	Easy
2132	What stereochemical result is expected when optically active 2-bromobutane reacts with OH⁻ by the SN2 mechani…	Chemistry Stereochemistry	Medium
2133	An optically active tertiary halide undergoes hydrolysis by the SN1 mechanism. What is the main stereochemica…	Chemistry Stereochemistry	Medium
2134	How do two enantiomers of 2-bromobutane differ from each other?	Chemistry Stereochemistry	Hard
2135	Why is chloroform stored in closed, dark-coloured bottles filled to the brim?	Chemistry Polyhalogen compounds	Easy
2136	What is the chemical formula of iodoform?	Chemistry Polyhalogen compounds	Easy
2137	Why was iodoform once used as an antiseptic?	Chemistry Polyhalogen compounds	Medium
2138	Why are freons harmful even though they are non-toxic and unreactive at ground level?	Chemistry Polyhalogen compounds	Medium
2139	Why does DDT become more concentrated in animals higher up a food chain?	Chemistry Polyhalogen compounds	Hard
2140	Which of these is a tertiary alcohol?	Chemistry Classification and nomenclature	Easy