Question

Predict the major product formed when an alkene reacts with a hydrogen halide (e.g., HCl or HBr).

• A. Alkane
• B. Alkyl halide
• C. Alcohol
• D. Ether

Hint:

Addition of hydrogen halides to alkenes usually follows Markovnikov’s rule unless peroxides are present (which causes anti-Markovnikov addition in the case of HBr).

Answer 1

The Correct Option is B

Concept: Alkenes undergo an electrophilic addition reaction with hydrogen halides (HX such as HCl or HBr). The hydrogen atom adds to one carbon of the double bond, while the halogen attaches to the other carbon. This reaction usually follows Markovnikov’s rule: \[ \text{“Hydrogen adds to the carbon with more hydrogens, and the halogen adds to the carbon with fewer hydrogens.”} \]

Step 1: Identify the reaction type. An alkene contains a \(C=C\) double bond, which is reactive toward electrophiles such as \(H^+\). \[ RCH=CH_2 + HX \rightarrow RCHXCH_3 \]

Step 2: Addition across the double bond. Hydrogen attaches to one carbon and the halide (\(X^-\)) attaches to the other carbon.

Step 3: Determine the product. The resulting compound is an alkyl halide. \[ \boxed{\text{Alkyl halide}} \]