What is formed when calcium carbide reacts with heavy water?

$A$ mixture of methane,ethylene,and acetylene gases is passed through a Wolf's bottle containing ammoniacal cuprous chloride. The gas coming out is

In the following reaction sequence: $Ph-CH=CH-Ph$ $\xrightarrow{Br_2/CCl_4} (A)$ $\xrightarrow{2NaNH_2} (B)$ $\xrightarrow{H_2/Pd-CaCO_3} (C)$,the product $(C)$ is:

When acetylene is reacted with $HBr$,we get

Identify the correct order of acidic strength for the following hydrocarbons:

Acetylene is prepared industrially by passing electric discharge through graphite electrodes in the atmosphere of