The number of $\sigma$ and $\pi$ bonds present in $pent-4-en-1-yne$ is

The reagents to carry out the following conversion are:

$Ph-CCl_2-CH_3 \xrightarrow{3NaNH_2} \text{Product } (A)$; Product $(A)$ is

An unsaturated hydrocarbon $X$ on ozonolysis gives $A$. Compound $A$ when warmed with ammoniacal silver nitrate forms a bright silver mirror along the sides of the test tube. The unsaturated hydrocarbon $X$ is ..... .

The reaction of $1,2$-dibromoethane with alcoholic potash yields.......

The correct order of acidity of the following compounds is

$I. CH_3-C \equiv CH$

$II. F_3C-C \equiv CH$

$III. CH_3-C \equiv C-CH_3$

$IV. CH_3-CH=CH-CH_3$