Board-style MCQs and naming / isomer questions in the BIEK / Sindh Board pattern. Tap an option to check yourself instantly. Solved questions are at the bottom.
Score 0 / 0Attempted 0 · tap any option to answer
Multiple-choice questions
Solved questions & self-assessment (past papers)
Give the IUPAC name of CH₃–CH(CH₃)–CH₂–CH₂–CH₃
Longest continuous chain = 5 carbons → pentane.
Number from the end nearer the branch so the methyl gets the lowest locant: C-2. → 2-methylpentane
How many structural isomers has C₄H₁₀, and name them?
C₄H₁₀ has 2 chain isomers:
• n-butane (a straight 4-carbon chain) → butane
• isobutane (a 3-carbon chain with a methyl branch) → 2-methylpropane
Why does but-2-ene show cis–trans isomerism but but-1-ene does not?
Geometric isomerism needs each doubly-bonded carbon to carry two different groups.
In but-2-ene (CH₃–CH=CH–CH₃) each C of the C=C has a CH₃ and an H, so cis and trans forms exist.
In but-1-ene (CH₂=CH–CH₂–CH₃) the terminal carbon (=CH₂) has two identical H atoms → no cis–trans isomerism.