When calcium carbide is added to water,the gas that is evolved is

The reagent which is used to distinguish between propene and propyne is

$Ph-CH_2-CH=CH-CH_3$ $\xrightarrow[(ii) \text{ Alc. KOH}]{(i) \text{ } Br_2}$ ?

Acetylene gas when passed through $20\% \ H_2SO_4$ at $80 \, ^\circ C$ gives acetaldehyde. The catalyst required for this conversion is:

Which alkyne will give $3$-ethylhexane on catalytic hydrogenation?

The acidic hydrogen is present in $ . . . . . . $.