Which of the following reagents is used to convert $\mathrm{C} \equiv \mathrm{C}$ triple bond to $\mathrm{C}=\mathrm{C}$ double bond to give Cis isomer of alkene?

What is the difference in molar mass of Undecane and Dodecane?

$$ \text { Identify ' } A \text { ' in the following reaction. } $$

A $\xrightarrow{\text { Lithium amide }}$ Ethynyl lithium $\xrightarrow{\text { Bromoethane }}$ But - 1 - yne

When 2-methylbut-2-ene is treated with hydrogen chloride, the major product formed is