Answer
There is necessary 1.0 mole of $SO_2$ to produce $0.50$ mole of $CS_2$.
Work Step by Step
1. Find the mole-mole conversion factors:
According to the coefficients: 1 mole $CS_2$ = 2 moles $SO_2$
$\frac{ 1 \space mole \space CS_2}{ 2 \space moles \space SO_2}$ and $\frac{ 2 \space moles \space SO_2}{ 1 \space mole \space CS_2}$
2. Use the mole-mole conversion factors to calculate the amount of equivalent $SO_2$ in moles:
$ 0.50$ moles $CS_2 \times \frac{ 2 \space moles \space SO_2}{ 1 \space mole \space CS_2} = 1.0$ mole $SO_2$
