The number of sigma $(\sigma)$ bonds in the molecule $CH_3-CH_2-CH_2-C \equiv CH$ is $......$

$2-$butyne is reduced to $trans-but-2-ene$ using:

The $C - H$ bond length is minimum in the bond formed by

$CH_{3}C \equiv CMgBr$ can be prepared by the reaction of:

The synthesis of $3$-octyne is achieved by adding a mixture of sodium amide and an alkyne to a bromoalkane. What are these bromoalkane and alkyne?

In order to complete the reaction $1-Pentyne$ $\xrightarrow{a} 4-Octyne$ $\xrightarrow{b} cis-4-Octene$,$a$ and $b$ will be:
$A) NaNH_2; CH_3CH_2CH_2Br : H_2, (1 \ mole) \text{ Lindlar catalyst}$
$B) NaNH_2; CH_3CH_2CH_2Br : H_2, (2 \ moles) \text{ Pd or Ni}$
$C) NaNH_2; CH_3CH_2CH_2Br : H_2, (1 \ mole) \text{ Pd or Ni}$
$D) NaNH_2; CH_3CH_2CH_2Br : BH_3, H_2O_2, OH^-$