Which of the following has the highest bond energy?

$Mg_2C_3$ reacts with water to form propyne gas. The $C_3^{4-}$ ion has:

When two atoms with electrons having the same spin approach each other for bonding,which of the following will occur?

$CCl_4$ cannot give a precipitate with $AgNO_3$ due to:

The potential energy $(y)$ curve for $H_2$ formation as a function of internuclear distance $(x)$ of the $H$ atoms is shown below.
The bond energy of $H_2$ is

How many bonds are present between carbon and oxygen in $CO_2$? Explain.